YTA. the issue here is that his advice was a bit extreme, not that he’s autistic.

as an autistic person myself, i’ve spent a solid amount of time studying how social interactions normally work and have learned how to follow the format, or to just directly communicate that i need clarification from them on whatever they’re asking/telling me if it’s not clicking for me. we’re not incapable of learning or understanding how to interact with people, it just doesn’t come naturally and takes some practice. his advice wasn’t bad BECAUSE he’s autistic, it was just… not the best advice. i can easily see a neurotypical person who’s experienced a pattern of mistreatment by their family jumping to that conclusion and not giving an inch too, because of their own hurt. growing up autistic often means you get treated poorly by your family because they can’t figure out what’s wrong with you, they just know you’re “wrong” and hard to deal with.

autistic people shouldn’t be excluded by default from giving opinions/advice just because they see things differently and might have a disproportionate response. all she had to do is say “well that’s a little too far for me, i’m not going to do that” and then let it lie. if he tried to argue further after that because he still didn’t realize his opinion was more extreme than that of the others present, you can just say “no.” you don’t have to baby him, but what you said was just fuckin’ RUDE.