AITA for wanting to cut my autistic brother off after he told me his most shameful secret?

This is a community like r/AmITheAsshole, except unlike that subreddit you can post interpersonal conflicts. Anything that's AITA including relationships, hypotheticals, even posting about Scar from the Lion King and trying to convince redditors that he was not the AH. AI scenarios/posts are not welcome or tolerated. An elaboration on our rules can be found here: https://www.reddit.com/r/AITAH/wiki/index