Wow, what a situation. I'm sorry that you are in the middle of all this and that your sister and her baby are having to deal with this guy. I agree with you that it is a blessing in disguise that he's getting deported. I hope it really happens - too bad he can be bailed out at all, that gives him the chance to disappear. If you are up for it, I would consider reporting him if he does contact her - better to have him stay in jail than get out and come after her.

With regard to the rest, it's hard to give specific advice since every state is different. You might try calling a domestic abuse hotline on her behalf or looking at al-anon support group schedules. Finding child care may be the hardest part. I would contact DHS -- do you have 211 in your area?

In terms of how much support to provide, there's only so much you can do. Your sister has to decide that she is done with him. It can be really frustrating to help people in your sister's situation- what you are doing by calling the police when appropriate and helping her secure child care is really great.