I have never understood why people just sit back and let stuff like this continue to happen. She needs to report him, and change her locks and whatever else is needed to keep herself and her daughter safe. This is probably why it's not a good idea to date criminals. I feel sorry for her daughter
If not for herself she needs to do something to protect her daughter from this weirdo. Quite frankly if I had someone who hit me, I would report his ass and move within 2 minutes of it happening. I hope her daughter doesn't grow up traumatized.