My brother (late 20s) and I (24F) live with our mom, who is on the older side and supports us financially. She pays the bills (except phone bill), helped him when he had no money, and even covered our college education. Despite this, he sometimes treats her with extreme disrespect—telling her “fuck you,” called her a bitch, telling her to shut up, and not doing anything to help around the house and ignoring her requests not to smoke in the house.

(EDIT: my mom doesn’t fully support us financially, just helps when either of us is in a bind)

That said, I don’t see my brother as a villain, and my mom is no saint either. We’ve had communication issues since I was a child, and these arguments aren’t new. My brother isn’t always like this—there are times when we get along—but when things escalate, it gets really bad. I’ve tried to mediate, but he often feels like I don’t take his side. After every huge argument, he acts like nothing happened the next day, which feels manipulative. I’ve suggested family therapy, but both he and my mom refuse.

After another argument today, I finally told him (condensed for anonymity):

“I want to be honest—not trying to start another argument, but because this matters to me. You’ve said a lot of hurtful things, and I’ve tried explaining how it affects me, but you ignore it and keep doing it. I hear your side, but I can only defend you so much before you cross the line. I don’t want to hear more meaningless apologies or that I’m your best friend, because your actions don’t show it. I feel exhausted and don’t know what to do anymore. I just want peace in this family, but something has to change.”

His response (also condensed):

“Fine. I’ve made my point for years, and I’m still misunderstood, so I’ll just be nonexistent. I’m fucking done and don’t want to hear it.”

I’m just tired. I worry about my mom’s health when these arguments happen, but my brother doesn’t seem to care. I don’t know if this is salvageable, and I feel stuck since I’m job hunting and can’t move out yet.

AITA for refusing to engage with him (like we used to) anymore?

Please provide tips on how I can make this work my family feels so broken and I have no one else to talk to.