If J recall, there are ways to catch legitimate cheaters,
C allows to use Aimbot, I suppose.
Why not ask him to type 'I love cats' or any phrase with 'c', while hes typing, walk around him, if he takes too long to type a simple text, he obviously is cheating, if he leaves and says 'crashed' after., hes cheating.
Also raven, can you post the whole chatlog if possible.