I'm surprised at the maturity of the kid. He mentioned that he would try not to think about what had happened, and focus on other things while holding back tears. That seems like a pretty grown up way to accept things and move on, I would of thought there'd be a different reaction.
Hopefully his family will give him some comfort though, losing a pet campanion is always hard to deal with but knowing that another person intentionally set the cages on fire (at least that seems to be what they've concluded) is probably something more difficult to deal with.