Oh, please, many kids (especially teenagers) would not even answer the direct questions from their parents about bullying and similar stuff. It is normal to just say "It's nothing, it's okay" and go cry in your room (and maybe even try to kill yourself), rather than sit and tell your story to your parents - even if they are truly caring and compassionate.
People who are prone to the real suicide are much more quiet about it than some drama queens who are shouting "I'm going to kill myself!" several times a day. Well, the same thing with the real homicide, too - even as adults we are prone to exclamations like "I swear, I'm going to kill that guy!", but these exclamations do not correlate with the real murders so often, right?
It is truly a challenge for any parent to admit that there is something wrong with their kid (not mentioning some crazy hypochondriacs and the like), be it a suicidal or sociopathical motives. In this particular case I personally would put more blame on the parents of the bullies, than on the parents of the victim. At least with sociopathy there are often other signs that are hard to miss, and often there is something wrong with the whole family - abusive or neglectful parents, for example, or some other emotional disfunction.