My little sister and my best friend moved in together. Purely as platonic friends. They both needed to save money. I told her not to do it. Because my friend is a jackass and his never gotten along with his roommates that I've known. On top of that my friend acts like he's bipolar but he's undiagnosed.

I talked to my friend beforehand as well. I told him that he couldn't raise his voice and yell at her. And that he needed to be a better roommate and friend to her. He couldn't treat her like he had other roommates in the past.

They made it a month before the first major fight of him being an ass. And my sister stubborn. And after about 7 months it came down to getting a lawyer involved to get his name off the lease. Because it became a completely toxic environment where she was sleeping with her door locked because she was worried that he might do something to her in the middle of the night. And the police were involved for potential domestic violence.

I told him he needed to move out and that he had to sign the paperwork with the lawyer. And that he and I were done as friends. Because he did exactly what I was afraid he was going to do and I had warned him about it. We had been friends for 10 years.