if he is the father, than he has rights to the child.
since a restraining order was established i assume that a court agreed with her that he can be dangerous. if the history of violence continues then when the child is born you could request limited visitation, parenting classes, and possibly counseling to be manditory.
but you can't really just cut him out of the life of his child. he has the same rights as your daughter.
of course, she could keep everything a secret, have someone else sign the BC (which would make them responsible for support - good luck finding someone willing to do that)or claim father unknown on the BC (he could come back and request DNA testing and establish he is the father if he wants) and just lie about who the father is (child will eventually have a problem with who daddy is and wanting to know about daddy). NOT A GOOD IDEA - this will all blow up in her face one day.