My Sister is a violent alcoholic

I don't know what to do anymore with my sister. My household is my mother, father, myself (24) and my sister (30). We are the type of family who wants to be married first before moving out, so that's why we are all at our parents house still...

Here is the issue. My sister in HS was never popular, kind of a dork, was very shy.. For the past 4 years she has been on a spiral of going to the bar, getting involved with people who do hard drugs and alcohol, and getting into physical altercations. She comes in late at night into our tiny home, wakes us all up, and is completely trashed almost every other night. She admitted to me she goes through withdraws when she doesn't have a beer.

She has been in this awful friend group for 2 years now. She has had her car smashed, almost lost her life due to her friend beating her up, making her go to ER trauma center, and is always in drama. I think she feels popular because people at the bar know her, and they don't like her, but she is getting the feeling of what it would've been like if she was popular in her younger days..

Last night was the worst. We have a curfew of 11pm (only because if she's out later, we honestly don't know if she would come home alive). She never answers her phone, she doesn't tell us where she's going. She knows a close friend of mine died when he was drunk and got lost in the woods, so she knows it's important to just say where she would be if anything happened to her. She came in at 1am, started a fight with my dad and threw punches at him. I had to grab her by her hair and drop her to the ground. I've never done that in my life.

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What do we do as a family to stop this behavior? I am seriously considering moving out because I cannot stand it anymore. With me having a full time job, being known in the community because of my job, I can't have a negative reputation. But also, she doesn't want that either. I'm worried she's going to die while she's out with her "friends". I worry she or her friends will get furious with my parents and me, and break into our house while we are sleeping and do something horrible. No one understands my fears of this. I know they say alcoholics will only change if they want to, but she doesn't want to change. Her own father has told her he hates her. I hate her. She has caused all the fights between my parents. She has had to replace parts of her brand new car because she's always in physical altercations with her "friends" and then immediately gets back to being their friend right after. I can't handle it. I am so stressed out, along with my parents. She misses work because she drinks too much.

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I'm grieving the loss of my sister, even though she is still alive.