Please help.
DSIS and her husband have been separated for around 5 months after he assaulted her, told her he'd kill her and held a pillow over her head, all in front of the children who were screaming. She called the police after locking herself in the bedroom, but was not supportive and didn't make a statement, he was interviewed but no evidence so it was filed.
Since then he has been staying at his mum and dads address. He has been continually emotionally abusive to her throughout this, saying he can't see the kids, he can't cook for them (??) and telling the children awful things about her.
She went very quiet so I messaged her and she said has now told me that he has asked to move back into the house and he will be there when she finishes work tonight. She is saying she wants no drama, and has been (IMO) way too agreeable and wanting to facilitate a relationship between him and the children. He says he will sleep in the sons room with him and pay her money (which, as I pointed out, he didn't do when they were together so is clearly not going to do it now)
I am terrified. Legally I feel she has really done an own goal and it will now be impossible to get him out. She says she will let him have the house now and find another one herself. But also this man is an abuser, he now has a direct link to her and she will never get peace, I'm so worried he will hurt her again, and the message it sends the kids. I've offered her our spare room. I've sent her links to non molestation and occupation orders. But she just keeps saying she will deal with it 'by stealth'. 
There's nothing I can do, is there?
Yabu - keep your nose out, she's made her decision
yanbu - anything else!