Hmm.... I don't exactly think it's right of your boyfriend to share so much with you his distaste for your brother. If he was more thoughtful, he would understand what a difficult position that puts you in. And if he gets upset because your brother is in trouble? This raises a red flag to me. How come he's not concerned? Even if he doesn't like him, he could be compassionate about the situation, by understanding that it's deeply troublesome when a family member is in legal trouble. Sounds like your boyfriend needs more tolerance and a bit of a talking to. I would explain to him how you feel and I would be very open and honest with him. He should understand that this is a family member of yours, after all. You cannot be split between the two, and he shouldn't be getting upset if you want to talk about it with him. This is raising several red flags.