I think that instead of just waiting for your mother to do whatever needs to be done, you need to be more proactive about calling the police, getting her connected with a shelter, etc. She’s much more likely to be killed at your home (as well as the rest of your family being in danger) than at a shelter because shelters have protections in place. I’m sure he knows she’s at your house — that would be the first place anyone would look. I mean, what’s stopping him from coming over one day to hurt her?
I empathize with all of you, including your husband. Helping is one thing, but helping and then repeating the process for ten years is a bit much.