My AH sleeps alot when he is trying to "control" how much he drinks. He has a few, then decides suddenly at 10pm on a Sat night, that it's bedtime. (He works second shift, and that's about 4-5 hours earlier than normal bedtime for us). Then he will sleep until noon the following day. (yes, thats 14 hours!) My daughter, the one with diabetes, also can sleep like that, and a real grouch to wake. AH will wake after those 14 hours, and it will seem like he has a hangover. I know it isn't possible, because he ran out of beer, and went to bed, instead of going to get more.....that's his way to control it...if he is sleeping, he can't be drinking...I suppose that's how he thinks.
Anyways, I think it might have something to do with my AHs blood glucose (sugar) levels. The liver has a lot to do with this function, so if it's not working properly, it can be dumping sugar into the blood stream, or not dumping enough, which in my own opinion, has something to do with sleep. It would also explain the grogginess once they finally awaken.....These are just my own opinions, I have no scientific evidence to back it up, it's just what I've observed of my AH and my Daughter. Add depression to that, and it's definately time to see the doc.