wake him up. My husband works nights and when he gets home he wants to play comptuer games, which i have nor problem with. I ended up making a curfew because he would never keep track of time and come to bed at like 8am!
well 5am was his curfew and whenever he wants on his days off...BUT he has to be up by noon. Thats 7 hours of sleep if he goes to bed at 5, and less if he chooses to stay up longer and then he has to deal with it because he brought it on himself.