Question: How does one differentiate between marijuana abuse and Kliene Levin Syndrome?

He smokes weed all the time and yet 2 or 3 times a year falls into a sleep coma like state for 7 to 10 days at a time. Looks like KLS to me but everytime I take him to doctors or ER they ask if he smokes pot. He says yes and that is the diagnosis. To me his normal pot use looks very very different from the sleep episodes which include, confusion, altered mental status, memory issues Extreme exhaustion, unable to focus or keep track of stuff. Nauseous and vomitting. Passive and child like behavior and sleep up to 20 hours a day for up to 2 weeks. Unable to go to work, not interested in driving, too dizzy and does not trust himself. Now when he is just smoking pot he is hanging with friends going places, going to work, and functionally pretty normally So why all of a sudden pot would lead to these much more severe symptoms I can't understand. I don't approve of pot use and I am not a user but I have seen a lot of people who use it and no one EVER acted like this from smoking. I am upset the doctors don't look past the pot use to see if there is a more serious problem that I should be getting him treatment for. Am I naive and is it just pot abuse?