Brother in law's girlfriend is abusive

 In August they broke up after being together for 9 months. She slept with a couple of her guy friends, whatever, but then in October they got back together and she wouldn't stop texting the guys she hooked up with so my BIL decided he was done. She got really worked up while on a family vacation, put a hole in the wall because she threw his phone, broke the screen, and punched him in the arms and face. He got really worked up and decided to leave the next day. I tried to convince him to stay, but I couldn't. He got in a really bad accident and his car caught fire. Then in the hospital his girlfriend, ex, whatever stayed with him and milked all the sympathy.

Now, she texted me today telling me she broke his phone again (this is the 3rd time since September) and she was laughing about it. They are always fighting, she's abusive emotionally and physically, but my BIL loves her so much he just won't give up. They live with my in laws and I can't believe they don't intervene; at least with the abuse... Something!

They won't come to me because I got nasty with my BIL for taking her back. He forgives me but won't discuss anything with me now...

Any advice? My husband won't talk to him... My husband is very quiet and not one for confrontation.