Whether this kid is nuts or not, he should have known better than to submit inappropriate content for a school essay. And from the article, it sounds like a previous assignment was also inappropriate.
You know kids, if you want to write slasher fiction, or erotic tales, that's cool by me. Go for it. But not in school. This is why there are blogs, and magazines and other outlets for stuff like that.
But the simple fact is that some content is inappropriate for some settings. Explicit sex, language and violence is just not appropriate in a school assignment. End of story, have a nice day.