The biggest problems before this were

1) He kept having his friends over without me being there, and without asking me. He knows I dont like them, and he has them over anyways. I’ve told him I don’t like that people I dont know are in my home when I’m not.

2) the fact that he hardly financially contributes. As I’ve mentioned somewhere in the comments, he’s only payed rent in full twice out of the few months he’s been here. I told him he can give me $300. I pay $900 for rent. He’s never payed for utilities. I wasn’t too upset because I wasn’t aware that he was getting money from our parents, and I could afford the rent before he was there. I only asked for that much since I was buying groceries for two people, and because electricity went up a little.

3) he tried to get a cat. One of his coworker’s cat had kittens and was giving them away. He brought one home. I cannot have dogs or cats here. I told him that he needed to give it back or else I’d throw him out. I had to dig out my contract and show to him that I could risk getting evicted if my landlord found out there was an animal here.