I registered specifically to reply to this thread, although I will post some other questions.
If domestic disputes are the most dangerous call for a LEO, why do you think you are qualified to deal with this? I have done the same thing as you, so I know where you are coming from. Your primary responsibilty is your family and your self.
My wife and I realized this about 10 years ago and now have a policy that I do not take people into my house. I will pay for 1 week at a motel and then they can figure out what to do. This goes for family and friends. If you let someone into your house for whatever reason, you may end up having to go to court to have them evicted. That takes time. If you get in an altercation with them, the cops may have you leave for the night if she has kids and says you have been in a relationship. Next time pay for a week and let that be your help.
If someone stays at my house, it is because I invited them, not because they are in trouble. After the hurricane, I did not invite anyone to stay at my house. There were shelters a plenty.
Is she is unwilling to leave the area to go to a shelter, she is not too concerned about her safety. Time to shout now... HOW DARE SHE BRING THIS DANGER AND POTENTIAL FOR VIOLENCE TO YOUR HOUSE. Shouting off. If she was that concerned about the situation, she would have called the police. If she wants the situation to get better, she will have to take action, not depend on you to take action. In my practice I have found that people that are unwilling to take action themselves to change their situation do not want their situation to change that bad. There is security in the relationship, even if it is abusive. Do not let yourself be sucked in.
Hope she gets it staightened out.
Ron