Merryways, the reason I assumed it was obvious that I - or his dad - would stay with him at a party is that when all the parents see him - (at the end of the day when they are picking their kids up, primarily) he is in his wheelchair. He can't walk. Perhaps it's me, but I am assuming that it would be obvious that we wouldn't just bring him to the party, park him in the middle of the living room on his own, or adbandon him at the front door (!).. and sod off!
Mymama, don't not invite the little boy in case soft play is inappropriate. Alex uses a wheelchair, but soft play is his favourite occupation in life! He can crawl and loves the rough and tumble of it all! I know this may not be the case for the child in question.. but invite him.. and his mum will soon tell you if he can't handle it. Then maybe you could invite him to tea on another occasion instead.
Re numbers invited parties, I have usually let my kids pick a selection - and then give the invites out with discretion and explain to DS or DD why this is necessary - because I haven't bveen able to afford the sort of party that you invite the whole class to. Except once when we hired a bouncy castle for the garden for DS1's 7th birthday. The whole class were invited to that. And re Alex, as I said, I specifically invited those that his one-to-one told me play with him the most/make time for him etc.
And yes, those who said it's the social thing (lack of) with the parents dur to Alex going on transport that is a bit offputting - I suppose that must be a factor. But I have to say, it wouldn't really be, to me. I would just give the invite to the teacher/TA. In fact I did that anyway, with DD's, last week, so that the teacher could put them disceetly in the books bags so that those we couldn't invite would not feel left out.
SJ x