I agree with emkee. If your father isn't sleeping as much as he feels he needs there is most likely a emotional phscological problem.
I just moved recently under unpleasent circumstances, and for the first week I was here I couldn't sleep for shit, ie not at all. So I started chopping wood. I know it sounds crazy but first thing in the morning I would drag my tired irritable self to the wood pile (I live deep in the northern wilderness so in the winter it isn't uncommon for single homes to go through 20-30 cords of wood, which is alot of frickin wood) Anyway, it got my mind off whatever was keeping me up at night and the physical work wore me out enough that I could sleep like a baby for 6 hours a night which is all I need.
I am not a doctor either, but I know from years of wrestling with a sleep disorder the most affective means of catching a few z's is engaging in some physical activity that gets your mind off your problems.
This is probably not the answer you are looking for but it works for me everytime.