You seem pretty perceptive about the nature of this guy. I have re-tagged the question for criminal experts. Please try and get your daughter into counseling and remain supportive of her. As much as you and I both would love to see her get a civil restraining order against him (as well as any criminal protective order); in reality, she has to be ready. Perhaps a domestic violence advocate could help her understand that abuse gets worse; without help, her life is at risk. Her custody of that child is at risk, too - be ready for a CPS investigation. Even though she is the victim, she has an obligation to protect that child from witnessing abuse - and that obligation must outweigh her fear. If your daughter loves her child and wants to raise her child, that boyfriend has to go, and she needs to apply for a retraining order and full custody. Good luck to you.
He could get up to one year on the DV case and they could revoke his probation on the other case and sentence him to state prison. Depending on the county, it is likely a conviction on the DV will send him to state prison because of the Probation violation, unless of course he is on Probation for a realignment case.
If he is on parole, he is definitely going to state prison.
Seth Weinstein, Esq.
Southern California Criminal Defense Attorney
This reply should NOT be considered a legal opinion of your case / inquiry. At this time I do not have sufficient factual/legal documentation to give a complete answer to your question and there may be more to the issues you raised then I have set out in my brief reply.
I agree with Mr. Weinstein. If your daughter remains with this idiot she will be behaving idiotically as well as endangering herself and her children. The police should have offered her a criminal protective order from this guy. If she didn't accept it she made a poor decision.