Everyone died going in for someone else—not the dog—in that the son who initially got into trouble going after the dog got out after his father went in after him, and then he and his mother went in after his father.
16 year old son went in after dog. When the son got in trouble, Dad went in after the son. The son and the dog got out on their own. Dad was in trouble, so Mom and the son went in after Dad. The daughter went for help.
I can't fault the Dad. I would have gone in after my child. I believe that my wife has enough sense, however, that she would not then go in after me or allow my child to go back in after me.
As a Dad, I would have no regrets if I died to save my child. But I would be really pissed off in the afterlife if that sacrifice only resulted in my wife and child dying too.