I wonder does he drink at all/much. I find that a beer or two at the end of the day makes me considerably more groggy the next morning (the length of sleep being equal). I think if I were to start waking up at 5 I'd have to eliminate drinking entirely. Probably a good idea but unlikely to happen.
I don't drink on a regular basis. If I drink on an evening event, then my limit is 3 pints, after that, I know I'm going to struggle the next morning ;)
Over the last year or so, I have significantly lessened my consumption of alcohol, and it has greatly increased my quality of sleep, but I was never one to oversleep because of drinking anyways. I will usually wake after only 4-5 hours after a night on the town. My biggest issue is getting to bed on time those nights ;) .
One thing that does help me out when I drink is to stick to spirits like whiskey and vodka. Beer seems to have much more of a draining effect on my body as do any mixed drinks with sugars in them.
