Unless he is abusing her or the kids, there is nothing that can be done legally to force him out of his own home. Unless.... he's not on the mortgage, which isn't very likely.
I think it's kind of a harsh reality, but if she wants out of the marriage, and wants to minimize the mental stress, her only option is to leave herself. She filed for divorce, she should have this plan in place anyway .
When I went thru my divorce, I LEFT HIM, I wanted out... I got out, and the only way he was able to bother me, was to leave me begging pleading voiemails, which he usually followed up with some of the nastiest messages I have ever heard - which actually ended up helping ME - when those messages were played for the judge, he granted my divorce without hesitation. :)
Edit note:
I wanted to add, that even when my husband verbally threatened me on voicemail and severely vandalized our car (saying things like when I was stabbing the seats I was thinking of you...) the police were completely unwilling to do ANYTHING. They told me 'there are no laws against vandalizing your own property' and 'without a restraining order we cannot do anything about him harrassing you on voicemail, even if it is threatening in nature'. It was this point I lost all faith in the police department.. and I walked out of there saying, 'well... when you find my body in a dumpster, you know who did it'. So I really wouldn't rely too much on what the police can do. Her lawyer is her best advocate thru all this.