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 We might be numb or withdrawn or shut down from already forging through a life we're not designed for.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. 

JuniperFromGallifrey said:

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'.

&

JuniperFromGallifrey said:

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...  

&

JuniperFromGallifrey said:

He won't understand how to be responsible as one needs to feel rewarded by it. 

Before I go offline I just wanted to say I really appreciate what you have shared here and echo some of those sentiments. I was a hugely abused child so the trauma left me with what's known as learned helplessness and I've discovered that this trap occurs a lot more frequently than people realise. It was only through tackling that learned helplessness (and as a result also rebuilt my confidence in general) that I then felt able to act on my greater ambitions.
I also am here in the dimly lit AM, and seem to have no innate sleep pattern but it's odd how quickly I fall back into being able to get up at 6AM and go to lectures (I'm a mature student myself) when my studies resume after the summer and winter breaks. If I understand you correctly then I too have noticed being responsible does indeed have a reward process, as sleep becomes a means to an end so I can function at my best and maximise my effort in chasing my goals now. So I do not doubt I will be in bed at a good time the night before the day back at studies. It's funny how it never occured to me until you said it but actually I believe you have accurately described the mechanism behind it.

JuniperFromGallifrey said:

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. 

Same. Although my mother was the abusive parent, dad didn't see it and I was expected to just cope. I would say more but usually people charge money for me to offload all my stuff onto them. And it's "a lot" figuratively and literally, so I won't burden you with the rest if you don't ask.

Anyway just wanted to say I found what you said really "hit home" and I couldn't have said it better myself.

JuniperFromGallifrey said:

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'.

&

JuniperFromGallifrey said:

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...  

&

JuniperFromGallifrey said:

He won't understand how to be responsible as one needs to feel rewarded by it. 

Before I go offline I just wanted to say I really appreciate what you have shared here and echo some of those sentiments. I was a hugely abused child so the trauma left me with what's known as learned helplessness and I've discovered that this trap occurs a lot more frequently than people realise. It was only through tackling that learned helplessness (and as a result also rebuilt my confidence in general) that I then felt able to act on my greater ambitions.
I also am here in the dimly lit AM, and seem to have no innate sleep pattern but it's odd how quickly I fall back into being able to get up at 6AM and go to lectures (I'm a mature student myself) when my studies resume after the summer and winter breaks. If I understand you correctly then I too have noticed being responsible does indeed have a reward process, as sleep becomes a means to an end so I can function at my best and maximise my effort in chasing my goals now. So I do not doubt I will be in bed at a good time the night before the day back at studies. It's funny how it never occured to me until you said it but actually I believe you have accurately described the mechanism behind it.

JuniperFromGallifrey said:

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. 

Same. Although my mother was the abusive parent, dad didn't see it and I was expected to just cope. I would say more but usually people charge money for me to offload all my stuff onto them. And it's "a lot" figuratively and literally, so I won't burden you with the rest if you don't ask.

Anyway just wanted to say I found what you said really "hit home" and I couldn't have said it better myself.

I don’t want to ‘feed my child to the wolves’ but equally when he turns 18 if he is still keeping me awake all night, refusing to seek education or employment, and generally being rude and unpleasant to the whole family, he is going to have to leave. I’m not going to feed, clothe and house an adult and subsidise their life of playing computer games if they are not prepared to at least contribute to the household by being respectful of others and helping around the house occasionally. For now he is being allowed to take everything and give nothing in return (and cause distress to his parents and siblings) because he is under 18.