Any ideas about challenges and issues of helping high functioning autistic person to transition into adulthood?

I responded to another post but it seems like you have a lot of the right sort of questions. 

For a start, I believe the school system is set up entirely wrong for Autistic kids. Which means, yes. Autistic children will not have been taught in the way which we are designed to learn. On top of it, they'll have been subjected to all kinds of maddeningly overwhelming nonsense which doesn't help us grow: too much criticism, rejection or sensory overload. Most aren't given practical understanding so all criticism is absolutely pointless if it's just negative and unhelpful unless provided with possible solutions. So, the first problem is, he might appear intellectually ready for Uni while being emotionally still in primary school. Psychologically, growth is stunted by trauma. And many of us are trapped as children, not being given explicit detailed understanding of how to 'do life'.

If he's on a different time schedule than most, it could be from all kinds of biological issues: no natural sources of light at night (LEDs and CFLs are all unnatural with too much blue light which is changing our ecology). Buy a halogen lamp for his room: www.lightaware.org.

But self-determination and agency will need to come before shifting a time schedule. A kid needs purpose to execute a bed time and not to be trying to problem-solve and resolve unresolved issues at midnight. Yet, here I am at midnight giving you solutions...  

Most non-autistic children will feel a drive to their societal time-schedule because they are wired for a competitive social structure and most schools are designed to help them mature properly with competition-driven structures rather than feeding their intellectual curiosity. So, He won't understand how to be responsible as one needs to feel rewarded by it. 

Which is a next point: Autistics won't build resilience, only resentment. We might be numb or withdrawn or shut down from already forging through a life we're not designed for. In an anthropological setting, there is the social tribe and then a few autistics with highly tuned ears to hear encroaching tigers and senses to perceive the slightest distinctions between toxic and healthy berries. Even colourblindness had a purpose. Colourblind men can see in the dark much better than those with 3 cones. They borrow from a wider spectrum of light. Modern traffic signs among other things are something they only learn to navigate around. They'll never actually see the colours the same - no matter how often they're exposed to it. They just need to learn a different way to see for matters of safety. 

Autistic children are better designed to sense-perceive environmental factors, but are typically shut down by their teens in modern society because they are not shielded properly or taught how to then work with potentially delicate "tools for calculation" - meaning our senses. Before a ruler or a leveller or a light reader or an ozone detector, we used sense-perception. Some are better crafting and mastering various senses than others. But technically, our ability to hyper-focus, make seemingly invisible intellectual connexions with hypersensitive receptors give us a particular edge. Yes, at the expense of more socially designed humans, but who would you want researching a drug to save your life? Someone who is worried about what the social collective think and saying what's needed to fit in? Or someone who can spot the nuance between 2 strains of bacteria and can't really understand why someone would lie about it for approval. 

Most likely, he needs help getting up to speed to where his peers at. What is he intellectually stimulated by? Encourage a focus of interest. 

We also need to feel a bit of relating with others. My son is now 25 but we love building legos together and making things. Just time spent doing this gives one a sense of being grounded in the world. This is relating with another through a shared experience. 

He needs to learn a type of self-discipline which he can use as a source of understanding to apply in other areas of life. In a perfect world, I'd set up a school where kids were required to take one self-disciplinary movement - judo, yoga, movement art, acrobatics, anything which aids focus and alignment with ones own physiology. Skateboarding even. We sometimes need to try a range of these to find out what we enjoy. Wall climbing, ice skating. And so on. Does he have anything like this he's interested in? This teaches a type of paying attention to the self and the vestibular sense perception. 

As for social engagement, he's old enough & might like the book F*vking Good Manners, by Simon Griffin blackwells.co.uk/.../9781785785511 I found entertaining and an excellent resource spelling out how to behave and why.

Once he feels a sense of competence and has more of a handle on relating with him self internally and the external world in a way which he feels a little more in control (try cooking or baking, woodwork, etc.) you may start to see a maturity. If helped to grow at our own pace (this would be different in autistic designed schools), we will begin to find agency, seize small responsibilities and perhaps be better fit for a career as we emerge. 

19 is young when one lives till 90. I was emotionally 10 years behind and my parents just fed me to the wolves, left me to fend for myself expecting I'd figure it out. I don't speak with my mother. I rarely see my father. I'm nearly 50 and hope to finally start Uni in a few years. 

This all strikes me as accurate with ref to my autistic son. He is traumatised by people (including us, his parents) not realising at first he was autistic and trying to deal with him as one would a neurotypical child. He stays up all night. Doesn’t go to school. Has no friends. Does no activities other than computer gaming. Has poor personal hygiene. Rarely leaves his bedroom. I can’t help him because he refuses any intervention and he isn’t mature enough to help himself. For example he doesn’t understand that a poor diet (junk food, Coca Cola at bedtime etc) contributes to his poor mood and lack of sleep. He doesn’t get any fresh air or sunshine. 
The problem is I can’t improve matters because he is not willing to change and just wants to hide from the world. As others here have said this is an under stable reaction to his treatment by the world so far and he is trying to avoid hurt. 
I would get him the book “fucking bad manners” but despite being literate he refuses to ever read a book. He hasn’t read a book since he hit puberty. The only thing he will do is watch films or play computer games. 
As you say, he needs a reason to have a routine and to be motivated to sleep at the proper time or whatever. But he doesn’t have a school to go to (we are currently in a legal battle to get a school to accept him) and he won’t engage in any activities (judo, sports, etc etc). 
i don’t know how to help him. And he’s doing my head in because he is keeping me awake all night. I’ve just bought earplugs which are helping a bit.

apparently halogen bulbs have been banned/are being phased out in the U.K.  

it’s all LED now for energy efficiency reasons  

LEDs. They're not entirely banned, not for those with light sensitivity. Have a look at lightaware.org  You'll be able to call around to hardware supplies and find them. John Lewis makes a cheap desk lamp which still uses an E24 bulb. I even have a selenite lamp which uses an oven bulb - spend a little time searching and you'll be able to find them cheap. LEDs deplete far more rare earth minerals. The lightbulb will eventually be seen as one of the greatest lies told to society. (if you're sufficiently bored, have a look at Planned Obsolescence and the light bulb)

This lifestyle is not healthy for him, Autistic or not. He's still Human. He needs vitamins (even if they're in the form of a multi-gummy), proper hydration, help with even a micro-schedule and something resembling sport. My son is 25 appreciates a quick work out and health, yet I still must remind him. I have also set reminders for myself, but am motivated to do so in order to stay alive as long as I can for the sake of him. 

From the research I've found, what makes someone an autistic human involves a few differences that change how we socialise, how we perceive the world, and how we are impacted by the world - all with a greater intensity in modern capitalism centred around competition. Our monotropic brain has natural difficulty with smash-cut changes or interruptions, while being capable of hyper-focus, accidentally seeing connexions others cannot, full-brain reasoning. And then, with less of an ability to filter sensory-perceptions, we'll have difficulty with unnatural or harmful chemicals / scents, sound levels / decibels, light, fabrics, GMOs, etc. BUT, I believe most of us can become extremely dependable at near-exacting calculation with these given proper mentorship to learn to calibrate our senses in a safe environment. Becoming a sommelier, foraging, music design, etc. Sometimes in order to learn how to explore the senses and understand the nuances in a palette, it's best to start with whisky or chocolate. I had no idea how many artisan chocolate companies existed, but it's quite impressive. It could make for a fun family evening.

None of our differences would really be a problem 100 years ago & it seems we used to articulate how to be civilised and how to be fluid in society if I look back into a research section of the library. And if someone was a bit more of a bookworm or engineer, they'd still have manners and we'd simply love them through their quirks, making accommodation for their odd socialising and terribly interesting obsessions. Today, not so much and the way most can just filter out sensory assault and diminish those who cannot is... 'fascinating' at best. Learning to afford dignity seems to be the giant hurdle today.

There's a fine line between supporting a child and leaving them to ruin. I'm not sure I'm always the best parent, but I've found classic wisdom is incredibly useful. Erich Fromm wrote a few good books worth looking at for your own sanity - The Art of Loving and the Revolution of Hope. 

Here's what I would do. Do not buy any junk food. Leave none in the house. If he wants a coke or something sugary, give him a few quid and let him go to the shop. Walking to the shop and stepping outside for a minute outweighs a bit of sugar. Pick battles worth fighting & suffer with him. Eventually, he may find he enjoys a quick walk. Perhaps it's a little bonding moment you share. A quiet stroll to the shop. 

The lack of sleep for autistics can be - not just from unnatural lighting, or from not properly exhausting the brain but for most of us, from an issue with GABA - a neurotransmitter similar to a 'resistor' on a circuit board. There are loads of new studies (finally) showing the relationship between Autism and ADHD regarding uncontrollable Gamma waves and it seems to be an issue with GABA. If there is something stuck in a loop in my head and speeding out of control, the only thing I've found to help is an occasional anti-anxiety medication. They're hard drugs, but in a 1/2 dose or less on rare occasions, I take them - a lack of sleep and that level of anxiety will cause a stroke at my age.

Video Games have been proven to lessen anxiety. They're not a cure. But they can create a great deal of relief. I'd recommend a full uninterrupted day once a week and then rarely the rest, but this can be a long-term goal. 

However, a lot of anxiety can be simply from a lack of wisdom, a lack of understanding the nature of things. This is much more difficult to fix but I've found philosophers and ethics really helpful. I used to listen to podcasts from an ADHD theologian and literally just life-wisdom helped to identify and distinguish isomorphic elements which were causing a great deal of stress. 

If he will take a multi-gummy and go for a walk once a day, you've won a few minor battles. That multi may have enough Vit D to help with mood just enough to get him to brush his teeth. 

Thanks. He does eat multi-gummies and I quite often do the giving him a couple of quid to go to the shop trick unfortunately he goes to the petrol station which is not far from the house so he doesn’t get much fresh air in the process (and it costs twice as much as the shop for coke!). Sports etc is a bit of a leap at the moment. He refuses to do anything like that.  I don’t buy a lot of junk food but he eats any that I do buy and if there isn’t any he eats cereal. He has ARFID and has had problems with food since he was about 4 years old. To be fair most of what he eats is not unhealthy, it is just bland (tortilla wraps, weetabix). 
I will look into the lights. As it happens I have a voucher for John Lewis :). It is very hard to parent him because he is prone to violent/destructive meltdowns which means his mum refuses to let me ‘lay down the law’ on certain things because of the reaction and consequent trauma to his brother and damage to the house etc. Can’t do a day without screens. Can’t even do 10 minutes without screens because I’ve been forbidden to take his screens away.  

JuniperFromGallifrey said:

not exhausting the brain

Funny coincidence you should mention this as I always felt like my brain and body were not being tired at the same time so one kept the other awake and vice versa for a lot of nights.

JuniperFromGallifrey said:

not exhausting the brain

Funny coincidence you should mention this as I always felt like my brain and body were not being tired at the same time so one kept the other awake and vice versa for a lot of nights.