My oldest brother is a grade A simp and I think he's going to end up getting hurt

My oldest brother is an artist, and you know how artists are - advocates for feminism and the like. He posts things like "I'm so tired of patriarchy" and is adamant that men are more toxic than women. To no one's surprise he has a crush on a girl from his class, who...afraid to say is a bad influence on him. She's a feminist and of course she hates men, but my bro likes to listen to her when she goes off on rants about how shitty men are. He constantly is defending her and says that she's the "only one who understands him". He's even started dressing more androgynously and pretending to be a more emotional "new man", and I think it has a lot to do with how this chick treats him.<br><br>I've spoken to other people about this, including my sister and cousins, and they all say that he needs to be careful. Apparently they've had to bail him out a few times because he gets blackout drunk and can't handle himself, and it's entirely due to this girl. I don't know how he's going to cope if she leaves him; he'll probably end up killing himself. What do I do?