IncogNeato:

If she's been arrested for violence, he should be able to get custody

Is it going to shock you that in the great state of Cali the judge would say something like, "Okay, it's clear that you two don't get along, but how is she with the kids?" and unless he has something about her hitting the kids the judge is going to figure that those kids need both parents and Bill may get primary physical custody but the visitation is going to be as close to 50/50 as they can manage. All her violence toward him will get is a restraining order between the two of them that means they'll have to meet in a neutral place to exchange or a third party will have to do it for her.

And the minute he accuses her of being a drunk she's going to accuse him of smoking pot and the judge will order that they both be subjected to random drug testing within 24 hours notice by opposing counsel for the next 18 years.

I told him, as much as he doesn't want to, as much as he wants to "win" this, he really needs to sit down and figure out how they're going to amicably look at each other during the custody exchange every Christmas Eve for the next 18 years.

This is a whole can o' worms he does not want to open!