Overheating 😓

I live in Texas with my parents and my little family are all crammed inside a small room that never seems to stay cool. I've tried sleeping naked and with a fan and nothing works. My step father loves to keep the heater in. As I stated before I live in Texas so we really don't have a winter it's more like fall so it's not that cold out. Any way I've explained to my step father plenty of times that I overheat in the room and whenever I do it causes painful contractions/nausea as I'm 36 weeks. I've tried to compromise by even turning the Ac off so it's gets neither cold or hot but he insists on having the heater on 72+. I'm not in the position to move so what other methods can I use to avoid overheating? I feel like I should sleep in a tub of ice, that's how hot it gets.