So they bullied a kid who most likely had no much longer to live and thought it was fine? The most likely reasons for an elementary schooler to be completely bald are progeria and chemo, none of which gives much hope to his life expectancy and both of which, combined with the bullying, explain his unusual interest in death, since it was somethng that could happen to him at any time.
The third most likely case is that he was clean shaved to avoid even further harrasing, but that white hair with that skin tone still points to some severe disorder that puts him on the verge of death.