Naturally, it looks suspicious. But its very likely the game mods have checked his games against programs. In correspondence chess, when one takes time and has superb chess knowledge, its easier to find good moves. Obviously, one with his record would need to ensure each of his moves were theoretically sound, and take fewer chances. It's impressive, but I know even the best programs are beatable by humans. (Except Hydra, a computational beast, which can look 16-40 moves ahead and soundly defeated super GM Adams 4 1/2 -1/2, a performance which, in my opinion, ends the man vs. machine debate)
I also know that there are a few books out there which show theoretically sound openings 20+ moves deep. I guess use of books comes down to ethics, especially while playing a game. When I play chess games, I intend to play against people, not machines or books. Humans are flawed, therefore, the games will be flawed. Mistakes and creativity make the game enjoyable. If you knew the game was going to be a draw from the start...why play?