Very good work by your brother, there. Artists are frequently their worst critics. I really like the mood he has in that second piece.
I'd just encourage him to keep plugging away, and maybe even take a look at posting some of his stuff over at DA to get a wider audience.
My Deviant Art page link-link
CoH/V Fan Videos
He's too hard on himself, those are really well done! 
I am trying to prove to him that he is a good artist cause...he doesn't believe me
so I am gonna post a few pics of his...he is prolly gonna kill me but it's totally worth it
bride
crying
and these 3 are part of a comic he is working on
harsent 1
harsent 2
harsent 3
Volt Sentinel Reference
Thunder is good, thunder is impressive, but lightning does the work.