All sounds very familiar.
He is very worried about having kids as a result of what happened to him and whether schools will be able to cater for any children he has, if they have the same gift. Which is a very strong possibility.
His parents tried to get his much less able (be still very able - now a doctor) older brother given extra tuition/scholarship at private school. The older brother didn't have the same behavioural or learning difficulties. So when it came to my friend his parents didn't even bother to try, even though he was in even more need of extra support, as they had gone through the process and got nowhere. So naturally that concerns him even more.
He gets very upset as he often unconsciously makes other people feel stupid, as he talks at his level as he respects the intelligence of others and assumes them to be on his level; not realising that its just going over their heads. Its not intended, he just operates at a certain level naturally - his problem is precisely because he does see others as equals and in no way looks down on them. As its so natural to him, he really struggles to adapt to the level of a 'normal' person even though he does have a very wide range of friends with different educational backgrounds. So putting him with anyone with a lower ability at school was never going to help him adjust to their level and it wasn't going to help them as he just encouraged them to mess about. From seeing him, and my own experience I really don't get where this idea of 'helping' the brighter kids really comes from. Its a theory that really doesn't work in a lot of cases.
Although I think my friend is an extreme case, I really don't think hes that unusual either.
youarekidding, it is entirely possible your DS could well be dyslexic like my friend and its not going to get picked up because he's so bright elsewhere - if hes got such a difference between his literacy and maths ability.
My friend does things like trying to use yellow tinted paper or read larger print books as they are things that help. His entire way of learning is very different from other people and he mainly self teaches or just memorises things.