that is a horribly sad story, i would have done the same thing, but i have to say the dad sounds like a real a-hole, obviously the dog meant a whole lot to his son, so why would he say such rude comments?
He sounds like an "a-hole"? Thats funny, to me he sounds like he is a man grieving the loss of his young son, who is probably pretty angry at the situation. Everyone handles stress and trauma differently.

RIP Justin.