My BIL (DH's brother) has two sons. Both are slightly neurodiverse but high functioning. Like some parents do he likes to show off about their achievements eg one is a maths genius and one is really artistic. They struggle in other ways eg communication, eye contact, obsessions etc but neither have a diagnosis. Their parents treat them like babies in some ways eg they still have their food cut up for them (they are 14 and 11), don't dress themselves, parents brush their teeth for them etc. whereas they are perfectly capable of doing this (and have done so perfectly happily when parents aren't around) so it's a really weird vibe in general.
What is upsetting is that BIL (but not SIL) takes every opportunity to criticise or put down my DS who is 13. DS is polite, mature, kind and capable so it does stick out when he does "normal" things that his cousins don't do. Like he would offer to make others a cup for tea while his cousins are having their dinner cut up for them and eating it with toddler cutlery. BIL criticises my DS or "jokingly" pokes fun at hin all the time. In the past I've just put it down to BIL being a bit overprotective of his sons and kind of wanting to even things out by praising his sons for doing basic things like put their shoes on (which they are more than capable of doing) while saying that DS's shoes make him look like a clown - just one example.
But my DS is starting to get really upset about it. BIL ignores my DD who is 8 as presumably he doesn't see her as being in competition with his DSs. Anything DS says he gets made fun of or criticised for. My DH has spoken to BIL about it but he gets all defensive and starts huffing and puffing and saying he's just joking. But he keeps on doing it and it's clearly not a joke and has a malicious undertone.
I don't really know how else we can handle it. It's sensitive as I think BIL clearly feels like my DS "shows up" his DSs differences and it makes him uncomfortable so he goes out of his way to praise his DSs while pulling down my DS. If it was just my feelings being hurt I would ignore it as I think he's not worth engaging with. But DS has to spend time around him and I don't know if I should be stepping up more to protect him from it or just accept that is how it is. DS is really mature and is aware of why BIL is behaving that way towards him but it doesn't stop him feeling hurt by it.
Unfortunately there's no escaping BIL as we are visiting family from overseas and DH and BIL's Dad has terminal cancer so we are having an extended "holiday" in thr UK to spend time with him.
Not really sure what I'm asking here as I don't think taking to BIL again will make any difference, and I can't remove DS from the situation as he is spending time with his Grandpa. Just wanted to see if anyone has any words of advice I suppose.