Need advice for wife of an addict

The wife in this story isn’t me, it’s my mother in law.

He is an addict and we are out of options. He’s been on meth for 2+ years. My husband (their son) and I have taken our daughter away from him in hopes that it would help and because we absolutely did not want her around it.

This was MONTHS AGO. And nothing has changed. In fact, he’s gotten worse. He sends my husband multiple texts a day about how “he didn’t raise him to have the devil inside” and “taking away my grandkids is the devils work” and lots of other really terrible things. Blaming him for the reason he’s on drugs.

He’s also verbally/mentally abusive to his wife. This isn’t new, he’s always been very mean to her but no where near the way it is now. My husbands sister and other brother still live at home they’re 23 and 18. She called him today and told him she’s walked in on her dad screaming at their mom “I just want to punch you in the face, if you took my side our kids would still be around, you’re the stupidest person I’ve ever met, what a mistake it was marrying you, you never stand up for me.” And again, lots more.

So this leads me to this. She wants to leave, as does her daughter and son. However, the hardest thing for them has been trying to figure out where they’re going to go. Has anyone else experienced something like this and could give me insight? She doesn’t know where to go, and kicking him out just wouldn’t happen and she can’t afford the house by herself anyways.

He’s getting to the point where he’s “tweaking” and I know nothing is stopping him from showing up at our house.