I am not a parent, but I can imagine the "Lucky he died" comment not being intended as a barb--not only for the reason RumR mentioned, but also b/c the father died with his boy. They didn't die alone. That might sound really weird to a bunch of folks, but to people who believe in an afterlife it may not sound so bad. Maybe that's just what was meant to be...
As for not putting his kid in harm's way--I don't get that. The kid was 12 and with his dad. More kids die in car wrecks every day than in climbing acccidents--yet I don't see people driving very carefully. I suppose it is easier for us to judge others than to look at the impacts our own daily actions can have on the lives of others.
He was a fortunate boy to have a father who shared life with him like this. I'll bet that kid saw and achieved more in 12 years than some people ever do. And what a great father to have shared his life, his love, and his death with his child. He gave absolutely everything he had to his child--who could judge that so harshly?