Can't help some people

I lost my Dad some 4 years ago. After that, my mom started seeing this guy. Seemed ok, but it didnt take long to find out this guy has a drinking problem. He's been verbally abusive and everything short of physically abusive.

One day I get a call from my mom...he's drunk and ripped her shirt. I book a flight and go to her. I get all his shit out of her house and the garage. Take it to him and make it clear he shouldn't ever come around again.

Fast forward a few months later, she's let him back in her life and asked me to be ok with it. Tell her "no" and we go through the same shit again minus me flying back to her. I call the cops and when they get there, they tell me they cant make him leave because he technically lives there, which he does not. I flip out on the cop over the phone, she stays with some friends, I got one of my friends to come change locks (we have a large farm with many buildings), and all goes quiet again.

Tonight I get a call from my brother. Shit has hit the fan again except this time she calls him instead of me. He tells me she asked him to get my 80 yr old grandmother to come over and try to talk some sense into his drunk ass. Brother calls the police and refuses to "help" my mom by sending anyone else to the house. He's upset because he thinks he's done the wrong thing. I told him we've done all we can do and there's only so many times you can rescue someone.

TL;DR : My mom keeps letting this asshole come around, and expects us to clean up the mess when he inevitably goes ape shit. I no longer care.