Sister and her bf

My sister(31F) and I(36F) live together. We’ve been living together our entire lives, when our parents died, we just took over the home we lived in and continue to live here to this day. She met her bf(23F) when she started working in October 2025. They started dating in January 2026 and she found out she is pregnant in March. She is due in November 2026. Her bf lives with his dad but as of recent he’s been staying over every single day. The home is a 3 story house. I’m a single mom to a 8 year old autistic child(8F). The fact that he’s practically living with us is making me uncomfortable. My daughter takes off her clothes randomly and doesn’t understand privacy (autistic) and she’s always had the freedom to be herself. Now I constantly have to make sure she keeps her clothes on because he’s around which really frustrates her. I can’t discipline her (put her on time out) because he’s listening to everything and it makes me uncomfortable. I hated it when my parents disciplined me in front of others when I was a child. I told her today it makes me uncomfortable and she said she pays the bills too. I told her paying the bills makes her entitled to space and comfort in the home but not to bring another person
in to live with us. She never asked if I was in agreement with this. Then she said she will just keep him in her room and I said that’s not doable either because everything can still be heard including my conversations with other people. She said she’s having his baby and wants him there. I love her bf he’s really nice but I don’t know him well and honestly neither does she…..they have been dating for 6 months.

TL;DR: sister lets her bf sleep over every single day, he’s living with us at this point. I’m not ok with it. What do I do?