Worried about my son

Stress and mood are like waves on a heart-monitor, except they should go a certain-amount up and an equal-amount down. If Matt is physically preventing himself from being overtly-concerned in a situation, his low-mood will not be sad as normal, but instead it will go right down into depression without resistance. 

The immediate-problem there is not with the willingness to validate depressive-thoughts and behaviours, the problem is with the disqualifying of positivity and the resistance to risk, Matt special-interests will help him justify-risk and feel-good.

So perhaps whenever the next Comic-con is showing, you could take him there, or whenever the next NEET course becomes available, you could urge him to sign up. But any push you make for development must be proactive in nature, don’t be proactive in combating a depressive attack, be proactive with his interest..:)

Okie dokie, What I will say is that the main-issues that I feel I’m trying to define here, is the difference between Matts special-interests and Matts problems.

The problems of autism as a root-cause is what I had mentioned above, regarding declaration and finding how best to introduce healthy-development. So it’s worth stating that, the way you expose Matt to new-experiences and regard what he has had difficulty with, is very-important. 

The problems with most-professionals is the way they train, they mostly have trained with psychology and behaviours in mind, which doesn’t lend itself well to neurological-issues like autism. Autists can have psychological-issues, but they need to be considered from an autistic-perspective and proactively. Usually therapists take a session or two to gather insights, then they disregard those insights and push a standard model, and say that people need to ‘just do it’. This doesn’t work for autists, because you can’t wish neurodivergence away with a can-do attitude, as it leads to overload. Which they learn to fear and avoid.

One of the ways that autistic-people deal with overload is to distract themselves with special-interests, though it can be a double-edged sword, because it can also reinforce safety-behaviours. Safety-behaviour needs modification, but you have to separate the behaviour from the special-interest, because the interest is what holds focus. So don’t throw the baby out with the bath water..:)

People can be very distressed when observing a meltdown or overload, but a meltdown or overload after a long-day is the exhaust of stress, so the real focus of meltdown-reduction should be everything before the meltdown, not the meltdown itself.

When a overload occurs you’re already too late, so don’t socially-interact with an autist and trigger-relapse by asking for explanations, just reassure them and have minimal social interaction, at that point special-interest is your friend.  
So I don’t believe that you should be shunning a special-interest. Once you know it you can use it, but to interact with Matt in a positive way, you’re going to have to do it through positive-form and proactively. When he hears you discuss his special-interest in a derogatory way, he will think that you think it’s bad, or you’re being evasive.

Matt being very-different in different places is a clear reflection of the stress he is under, whilst outside, if you felt that bad when you were doing something, you’d likely what to say in too. So I’d say that you should focus your energy on averting the stress, where Matt is masking most, I don’t think you should see the badness in the place where he feels safe.

He has interests of a child at times but at other times can be more grown up.

Professionals didn't understand him, they would dismiss his autism and put a lot of pressure on him which unfortunately did make him worse and caused him intense meltdowns.

Yes, different environments make this difference in him more noticable. At home he's not too bad but when he's out Matt is very different.

So are you saying that his interests are the interests of nine year olds? Or are you saying he has the mental capacity of a nine year old?

What was it, did you consider, was the reason his contact with professional was aggravating things..?

What did you consider ‘split personality’ to mean in his case? Was it the change in his mood of stress levels in different environments? Say the home and in public?

Thank you for explaining about masking. This is useful for me and his mum.

He still plays with his toys and make believe games. Mentally I would say Matthew is more childlike like his mental age must be about 9. Sorry if I wasn't clear before.

Autistic-people tend to learn outside of declaration, they tend to learn through procedure (procedural memory/learning) and through following-others example (rote memory/learning).  
So I suspect that what you are seeing is the result of peaks of ability, from exposure to things that he has seen and been allowed to proceduralise, outside of the realm of declaration/lecturing.  
Autistic-people learn best through exposure to their interests, there is something about his current special-interest, that piques his interest more than other exposures in his life, as such he is becoming more-competent in places where more-interesting exposure is opportune.

Hi John, could you elaborate on what you mean by ‘play’ and ‘like a child’, if I may be so bold..?

maybe masking.

he cant go out in the world and act like a child like you know him as.... he will be mocked and ripped apart in this society. so he puts on a act, a mask, to fit in with the world. maybe he acts hard, i dunno what kind of mask hed pick but for a man a strong hard tough persona would fit as it would keep trouble away add protection and get rid of anything to mock him for. and in this world as a man make him fit in more. 

its about being a chameleon, changing to fit whatever group there is to try fit in with them. only you will know his true self, all his "friends" or associates will never know him like you do. they will only know his facade to fit in with them. he would likely be embarrassed if you exposed him to them as it breaks his facade and exposes things he knows he will be mocked and alienated for.

Bumping this as I really do need guidance for my son.