Lil Update* Long story* bare with me. Need advice on dealing with sister and do you think I’m in the wrong for how i feel about her?

So my sister is 14 months older then me (I’m 21 she’s 22). She has a 2 year old daughter and when she got pregnant it was on accident from a one night stand so she was not prepared at all. She instantly changed her lifestyle because she felt so blessed to be pregnant. I was so happy for her and couldn’t wait for lil baby niece to get here. She used to smoke a lot of pot and drink and do cocaine but she stopped it all I was so happy for her. I ended up falling pregnant as well in the middle of her pregnancy and we were super excited. Me and my sister have always been very close. I miscarried two days before my niece was born :( she was kind of like my saving grace in a sense. Last October we moved in together (me and my boyfriend + her and 2 year old) so now that we live together I am seeing a lot of things that I just don’t like and she likes to shove shit in my face that really isn’t ok I’m my opinion. One thing is she is a heavy heavy drinker. No problem drinking but she drinks 3 6 packs a night and stays up till 4/5 am getting drunk while her daughter is sleeping and then since she’s tired and hung over from staying up so late she’ll force my niece to stay in bed with her until 1/2pm, my problem here is she forces my niece to go to bed at 6pm regardless of when she gets to come out to the room. And if she’s crying and not sleeping she’ll yell “go to bed” until she finally does and sometimes it takes a while. She also locks the door on my niece so she can’t come out. So my niece is only getting 5ish hours outside of her bed every day and she doesn’t get to play much. I told my sister when I’m not working I don’t mind watching her so she can play more but she tells me “oh *nieces name* is just really tired” well I HEAR her asking her mom to get up through my walls so i know she wants to leave the room just can’t because she locks the door and she doesn’t know how to unlock the door. I feel like she’s not being the mom she should be but it’s not my place to tell her you know ? And whenever parenting topics are brought up and she talks to me about things and i tell her how I feel about something (I always say “personally” or “when i have a baby” because I don’t want her to think I’m telling her how to parent because I don’t think it’s my place) shell go on a drunk ramble on how “well you’re not a mom and you won’t know any of this stuff until you become one” and it really hurts my feelings because I lost what I really wanted and she says that to me on a weekly basis so I just stopped talking to her about parenting stuff. And then she realized I stopped talking to her as much and now she’s like “did you hear about * insert miscarriage topic*” and it honestly makes me cry in my room a lot. My bf is not ok with what she does (he’s a father and has a 13 year old) he doesn’t like that she goes out of her way to make me feel bad regarding my miscarriage and he doesn’t like what’s she’s doing to my niece. We just really feel bad for my niece but obviously cant really talk to her about it because it’s not our business. I just don’t know what to do. Do i cut my sister out of my life when our lease is up and tell her to find someone else to room with?

Edit to add* my sister lives off child support and gov funding. She sometimes also babysits/nannies but currently isn’t at the moment. I didn’t know if I had a case and that’s why I asked. Also since I’m not a mother , I didn’t want to step out of line since she always tells me “you’re not a mom” and “you just don’t know what being a mom is” so I had no clue what to do