To get catatonic like that takes one heck of a lot of alcohol, or some kind of knock out drug. I've seen it, usually with the underage(18). It wouldn't surprise me come to think of it if it did happen. The perps got the worse conviction, not the "lesser" charge, also a felony.
I saw it once with an 18 year old, so I know it is possible to get that drunk, but it seems to be a somewhat rare occurence. It's also true that the date rape drug is something that would do that approximately 100% of the time. Unless someone steps forward and says they gave it to her, we'll never know.
Did I read it wrong, didn't the two perps only get six months and one year respectively? I realize they got a felony conviction, but that sentence seems a little on the light side to me.