Concerned about my dad's condition

I made this profile for my dad. I'm concerned. I dont know a lot about hid condition because my mom's been managing it in another state for the last 4 years. every once in a while he will fall asleep and be unable to be woken. his numbers are fine. oxygen levels are good, pulse is good. I dont know what it could be and it scares me. last time he went to the hospital and they didn't find anything. he has been asleep for the last 4 hours without getting up for the bathroom etc.. he takes water pills so I know he needs to go every so often. might be tmi, I'm sorry. any insite would be greatly appreciated. also when he finally wakes from one of these episodes he is in a bad mood. not sure if it's connected but he's usually a very happy person.