DSS is 11 and neurotypical. My bio DS is 6 and has autism.
Almost all of the time, whenever DS tries to engage his brother about anything, DSS just blanks him and it hurts me.
Today DSC were here and DS asked him how was his day at school, he looked right at him but didnt answer. I wish it was an isolated thing but it isn't. It happens every time they're together.
Occasionally DH will intervene and say "DSS, DS is talking to you" and DSS will begrudgingly answer him after he blanked him the first few times DS said his name.
DS has tried to use gaming as a 'way in' as DSS is a big gamer and loves roblox etc. If he asks DSS questions about roblox or wants to show him his character he couldn't be less interested and doesn't even pretend to humour him. If my other DSS wants to chat to DSS12 about roblox or gaming he happily engages.
There is no messy history. DH wasn't in an established relationship with DSC' mother so there's no broken home or toxicity. DSS' has a happy home life with his DM, SF and other siblings (the youngest one belonging to her now DH)
DSS used to enjoy DS' company when DS was small and cute but he has no time for him at all any more and sees him as an inconvenience.
DS and DH share a birthday (it's tomorrow) and DSS made a handmade card for DH but not for DS. He knows it's DS birthday tomorrow and remembers clearly that it's the same day as DH but not so much as a "happy birthday for tomorrow" from him when he went home.. yet he spoke with excitement about it being his youngest sisters 1st birthday next Monday.
I know siblings can be annoying and he's entitled to feel however he feels, but surely he should still treat DS with respect?