<human>: Condense the text into a few key points

Both my sister and I live with my parents. I'm finishing up my last year at community college before I transfer, while my sister, lets call her Kim, finished her undergrad last year and recently got a job at a company that is head-quartered near our house. 

While working there, she met someone, lets call him Mike, she really liked and they started to date. Everything was going well for them until a party that Mike threw about two weeks ago. At the party, Kim got upset because Mike was kind of ignoring her, she didn't really know anyone at the party, and it seemed like Mike was flirting with some other girl. After everyone else had left, Mike and Kim got into an argument about this, and they were both pretty drunk. Mike ends up kicking Kim, throwing her phone across the room, and engages in a lot of verbal abuse against Kim. It also comes out that Mike was abused as a child and has anger issues.

Kim comes home and tells me all about it. She says she's written down everything to remind herself of what he did and that she's never going to see him again. However, she just spent the weekend at his house.

I've repeatedly conveyed my opinion that she should not see Mike anymore, however she keeps telling me that its her choice. I'm thinking about telling my parents (They don't know) because I'm worried for her safety. She says she would never trust me again if I did. What should I do?
<bot>: My sister recently started dating a guy who abused her. He apparently has anger issues, but my sister is still seeing him. Should I tell my parents?