Yeah, sure he's whiney. That's because he's pissed off. Wouldn't you be pissed off?
Imagine you were tossed what you thought was 1000 years into the future, in a time when your home and home city is a pile of rubble, your dad essentially has become the devil, and all your friends in the past were killed by an attack by sin. As well, nobody believes you, and the devil (aka Sin, or your "old man") keeps showing up, killing thousands of people and destroying entire towns in his wake.
I think you'd be pretty pissed off and whiney too.
Ya gotta commend him for his confidence, bravery and leadership despite all that.