Seeing as I got an honorary mention in the thread title (takes a bow emoticon) I 'suppose I'd better respond... 
As an exercise I think it is fine. I don't think death should be a taboo subject in school. TV and film are awash with it after all.
Teachers are used to dealing with classes of kids with "issues" - they come up all the time. I was in a class that were doing a lesson on Sherlock Holmes. The 12 year olds, lower ability set, were mostly interested in his drug taking. "He was a junkie like my ex-dad!" one commented.
Problem seems to have been when the 14 year old showed it to his mum without saying "this is homework - I'm not really planning to die any time soon , good night, love you mum"
But 14 year old boys are not known for their emotional intelligence.
Many of them seem to think for instance that spitting is a good way to impress girls!
So have the parents in their considered wisdom contacted the press? Instead of expressing their concerns to the school. Give me a break!