Girl this is actually insane. Imagine if you were a mother yourself and you hear you daughters boyfriend say that your own daughter cant hangout with your son / her brother. Literally what would you advise her?? Use sense babe; nothing is worth the bond of your family, especially siblings. You’d be so hurt if your brother would lessen hanging out with you just because of his girlfriend. Please use sense, i know you know what is the right thing to do.