Son's behaviour more obvious as he gets older

You might be hitting the point where he's so wrapped up in his interests that he's unable to spot the small and continual changes with all of his peers.   We're not good at spotting body language and non-verbal communication so there's a risk the changing social scene will leave him behind simply because he's not looking for it and not expecting it.

What sort of relationship do you have with him?   Does he understand he's different?    If so, try chatting to him about life and the changes coming up and try to pre-arm him with the inside track about what's really going on - what to expect and how to deal with it - all the permutations and combinations and what to watch for in his peers.   Give him all the clues about potential pitfalls to watch out for.   Keep it up-beat, non-judgemental and positive - avoid emotional content - it's just knowledge & data.

Don't try to stop him doing what he loves - but spoon-feed all the necessary data for him to be able to fit in.    He'll probably spot it on his own - but probably years too late to be able to catch up - he'll already be left out of the social scene.

Some people are likely to jump on me for encouraging him to mask to fit in - but it's the law of the jungle out there and school life can be harsh if you're different.

There's another trick - get him into something cool - like mini-bikes or whatever is considered a cool hobby in your area - so he becomes someone worth spending time with rather than being shunned.

There's another trick - get him into something cool - like mini-bikes or whatever is considered a cool hobby in your area - so he becomes someone worth spending time with rather than being shunned.