It's very unfortunate that he doesn't get along with his mom. Mothers play an important role in their sons' lives and, although you are his girlfriend and it's a given that you will support him, you need to take a neutral approach to the matter. Encourage him to talk to someone he can trust (like a brother or his father) but it's best that you don't get more involved than that. Make sure you never develop an attitude towards his mom. Remember - she's an adult and also the mother of the guy you love. Whatever you do, be a good listener and supportive girlfriend - h''s going to need you. We hope that they solve their differences soon!