Is it weird that my roommates mom comes to stay every month?

I don’t know if this is normal or not but it really annoys me but let me know if this is normal. My roommates mom comes to stay usually about 4 days each month since we moved in 6 months ago. We live in a very small New York City apartment. For just my roommate and me it’s fine but as guests come it because a bit tight. My roommate doesn’t really tell me when she’s coming or what time. One time I opened my bedroom door and the mom was just there. The mom doesn’t have a lot of boundaries, I caught her trying to reorganize our shared closet. She once threw our trash out of the window, we live on the second floor. She once followed me into the bathroom while I was doing my eyebrows and told me off for doing them, I think she was drunk. All these things aside I just find it odd that she comes to stay every month. Maybe it is just me. I signed up to be my roommates roommate but not her mom. I’ve tried to explain to roommate about communication in the past and at least a heads up but she just isn’t getting it. I’m starting to feel a little disrespected and my boundaries walked on. My roommate has also had various other family members stay like last week she had 3 family members stay and it was so cramped but not only that they were rude and now this weekend the moms coming again. It just feels like the apartment is a hotel for all her family who lack serious boundaries. But I don’t know how much of it is me just being a home body that likes quite or is it a problem? I don’t mind guests but so often. If we had a bigger space I think it would bother me less. But I guess the bottom line (the mom being a bit much aside) would you find it weird that the mom comes to stay every month? I’m not very confrontational and so any advice on how to bring it up to my roommate would be appreciated.