I (20M) live just up the road from my parents, mostly so I can stay close to my little sister (10F). She’s disabled and I worry about her a lot. My current place is cheap thanks to my best friend’s mom, who’s also my landlord and really supportive.

A little background: I moved out at 18 to get away from my dad (47M). He was abusive to me growing up physically, emotionally, all of it. My mom (40F) has also been through it with him. She has bipolar I and II, and he’s always used that against her.

Gaslighting her, telling her she’s just “crazy” and imagining things. He won’t let her go anywhere without him, even her doctor or therapy appointments, and he keeps her completely isolated. She also has a heart condition that’s triggered by stress and heat, so yeah, that environment is not safe for her.

Recently, my dad called me early in the morning saying “your mom is acting crazy” and that I needed to come pick her up. He claimed she broke his PS5 and was throwing stuff at him “for no reason.” I know from experience how that usually goes. So I jumped out of bed and picked her up.

When she got in my car, she was crying and shaking. I’ve never seen her like that before. She told me she was done and wanted a divorce.

Long story short, she’s now staying with me and my roommate, thanks to my landlord/best friend’s mom offering her a safe place to crash. Since she’s been here, she’s doing a lot better. She can go out, have friends, and actually breathe for the first time in years. She’s still on edge, though jumpy, scared, just not okay yet. And to make things worse, on her second day here, my dad showed up at my house, banging on the windows and doors yelling “I’m looking for my wife and my son!” like he didn’t know I lived there. (???)

I didn’t answer, and my mom literally crawled into my room scared he’d see her through the blinds. She has chronic PTSD and has panic attacks pretty often. She’s not exaggerating, he really has put her through hell.

Back when I was a teen, she tried to end her life and ended up in a psych ward. She told them about the abuse and got placed in a shelter for a few months. But when she got out, she went back to him. He had been begging police to let him see her again. She thought she still loved him and tried to make it work. Then she caught him cheating with a girl from GameStop, of all places and that was the last straw emotionally. But by that point, she was stuck again.

He’s always kept her under control. He even made her disability payments go to his bank account not a joint one like he claimed. She doesn’t even have a bank account or a driver’s license. He gives her $20 a month from her own $850-900 check and keeps the rest. Same thing with my little sister’s SSI. She needs speech therapy for a disability, but he says they “can’t afford it” meanwhile, he’s buying expensive tools and paying off a fancy car. He’s unemployed and hasn’t held a stable job in years. He just keeps blowing money and not caring about anyone else’s needs.

Now that my mom is safe with me, she’s getting some freedom back, and my dad is losing control and he’s not handling that well.

So… AITA for letting her stay with me, knowing it would make my dad angry and he might start showing up at my house?

Personal or legal advice appreciated!