Been there, done that, bought the T-shirt, use it to wax my truck.
In my younger and dumber days I went through a bunch of those. I'd find them practically laying in the dirt, pick them up, dust them off, dry their tears, get them on an even keel, and watch them run right back to their abuser. Some women, and some men, are drawn to people who are down right nasty to them. I still don't understand the compulsion but I've seen it first hand and can tell you it is very real.
I picked up two things in your post that need to be recognized and dealt with. First, he will continue to use every bit of influence he has or can acquire to manipulate her. The children are no exception. Second, its common for abusers of that type to need to increase their level of abuse over time. She needs to break off contact with him yesterday if not sooner. The idea that she and the children will be safe until the children turn 18 is a false assumption. She is in physical danger right now. There is no way to predict when the psychological abuse will become physical abuse but odds are that it will.
But the bottom line is this. An old joke asks how many psychiatrists it takes to change a light bulb. The punch line is it only takes one, but the light bulb has to want to change.
Until your light bulb wants to change, until she recognizes that her behavior, while getting her the empathy and attention she craves from others, is in fact destructive, and resolves to make some drastic changes, there isn't a God damned thing you can do.
Something I read years ago:
Harry Truman showed us any man can be elected President.
Franklin Roosevelt showed us a man can overcome any obstacle to be elected President.
Dwight Eisenhower showed us we don't really need a President.
Richard Nixon showed us that might not be such a bad idea.
If I block someone, it's because I don't want to read their posts. Yet of someone quote's them in a reply, I can still see it. I was told this was going to be referred to someone who could investigate and perhaps come up with an improvement.
We'll see how it goes.
As Buz noted above, Petty was from Gainesville, home of the University of Florida. I was a student there before his career took off and saw a number of his free concerts with his band set up around an outdoor fountain at the Reitz Student Union.
Years later I heard one of the Miami rock DJ's telling a Petty story on the air. It seems that there was a music store in Gainesville that supported the local rockers. The store sold sheet music, vinyl albums, tapes in various formats, and all sorts of musical instruments. The owner encouraged the local musicians to try out the new stuff at a bandstand set up in the corner of the store. If they tried a new guitar or piece of gear they liked, he fronted it to them and allowed them to pay it off over time. Years later, when the owner was selling the business and going into retirement, Tom Petty and the Heartbreakers put on a benefit concert in Gainesville with the proceeds going to the music store owner's retirement fund. It was their way of supporting the guy who supported them. I thought that was a very fitting thing to do. Put me down as another saddened by his untimely death.
Rocks, a finger of Wild Turkey 101, and Coke with all the stuff in it.
In my experience some were better to look at than others. But I've never actually met an ugly one ;-)
Besides....
They're not really for looking at!
Legs.....
Spread the word!
;-)