AC in kids room

My stepson is 12. Last year we put an AC in his room for the summer and it was always on. Literally always and he would lock the door so we couldn’t go in there and turn it off while he was sleeping. If him and his sister got picked up by their mom they would leave the big ac on. They got picked up at 5 and my boyfriend and I didn’t get home till midnight most nights. We have moved houses and the way this one is set up having just an ac in the living room actually cools the rest of the house down fine. I mean we live in Chicago it hot 3 months out of the year. I suggested we don’t put one in the boys room this year. I had bought a little portable ac that cooled off my room with me, my boyfriend and my son sleeping together. My son is 18 months old and he was premature sleeping in a diaper in the middle of December because anything else he would just start sweating. So I feel if that portable ac can keep the baby cool then it’s just fine for the 12 year old. But he’s throwing a fit now and my boyfriend is mad at me. With this covid stuff we are a month late on rent, the light bill hasn’t been paid. I don’t want the money of an extra ac right now. Would y’all put an AC in his room?