that reminds me of the time marijuana nearly killed me >< i was smokin a fat ass sweet and you know how sometimes it will make your sinuses close up so you have to breathe out your mouth? well i had to throw up and i started puking my fucking guts out and i couldn't stop at all.....so here i was throwing up so bad i couldn't breathe through my mouth and my nose was so clogged i couldn't breathe through it .....man that day sucked.....but i went right back to the room after brushin my teeth (lol) and smoked another.....made me feel all better but yea...i've never heard of that....here's a possibility, one of you other friends had a germ/virus on them that their immune system was already working on and gave it to your friend and his didn't reject/fight it so he got sick....that's about the most logical solution i can think of....never had a hangover with weed lol