Haven't looked at the demo's yes (still will), but since he seems to have been banned before:
http://www.dswp.de/old/lamas-corner/dafuq-t6005.html.
I'd say you should be a little harsh on him.
I will look at the demo's now and update my post later
EDIT:
It does look like a wallhack to me from time to time.
Reasons:
He does not look around very much, he goes into some place straight and fires, does not have to look for enemies.
Although because of the situations where I could certainly say it is a wallhack are so few it could also be luck.
Other things:
Unpleasant playing style, he does not forgive if being asked to do so, retaliates by a tk. And he also spawn kills.