Need advice!

I work at night so my fiancé is on baby duty and EVERYTIME I come home I find our 3 month old sleeping in the swing with a big blanket on top of him and an empty bottle propped up on it so he can feed himself while my fiancé sleeps. We’ve had so many fights about this and he keeps saying he’ll stop but he doesn’t. I don’t want to come home to find out our baby has suffocated or choked or is covered in spit up because he wasn’t burped. He doesn’t get how dangerous it is. I’m tired of fighting with him about it but he’s too lazy to put our babies needs and safety first.