What do I do 🤔🤔🤔

What do I do????? I live in a studio apartment. Myself my boyfriend and now my mother all live here in this small studio apartment together. There is no real privacy unless in the bathroom alone. We're trying to get another apartment but I'm also not working since my mother has kidney failure, heart failure, brain damage from two strokes, high blood pressure, and diabetes. She also has cataract. My mother tonight told me that she was asleep earlier this morning and turned over and caught my boyfriend masturbating. She said that he was humping the bed. I was asleep. I don't know what to do about this though. When I confronted him he said that he wasn't. He says that he was turning over because he couldn't get comfortable but normally in the early hours of the morning he'll masturbate at least 3-4 times. I have sex with him just not while my mother's home. My boyfriend has a very strong sexual appetite which makes him want sex all day. But when my mom is home I can't do anything..well if my mother has caught him masturbating I don't know what to do because he does it in our bed but he doesn't put his genitals into his hands. He just humps the bed. 😂😂😂 What should I do to help my mother? How can I stop this situation? I don't know what to say or do. I went off on him about respecting my mother, about masturbating in the bathroom and about waiting..I apologized to her and tried to explain to her his problem but I feel very embarrassed and angry. What do I do?