Lvn this must be extremely hard to deal with knowing that shes being abused. I have been there and I do know what its like, and I know that when you are in a situation like that you WANT someone to help you.
I say the best thing you can do, even though it will be dangerous but well worth it, is try your best to talk her into leaving this guy and getting some support from a local community help center. There are places that people like her can go to get help, and to get away from this guy. Let her know she IS worth it, and that she doesnt deserve to be hurt like that at all. It may take time, God knows the custody battle between my mother and father lasted 6 months, but it is well worth it in the end.
If you love her as much as it sounds like you do... help her and dont give up on her. In the end she should see that.

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