Everyone seems to be blaming the parents, but I blame the kid.
Seriously, this is a 15 year old, not a 4 year old. At that age he shouldn't need his parents hand holding him for basic stuff like staying hydrated, eating, sleeping, etc. What he did he did of his own volition. Plain as that. The consequences of HIS actions was hospitalization. His parents should be checking in on him *you know to make sure he isn't dead or something*, but having to do the above is pretty much overkill for someone his age.
I hope the parents don't get too penalized for their sons lack of judgement. At his age, he needs to take responsibility for his actions.