Maybe, but perhaps not.
I have heard that the general standard of play in live is much stronger than correspondence. For that reason, people generally have lower live ratings. Of course, a 1000 difference seems a little strong, but who knows? He may spend a lot of time on correspondence moves.
...for someone to have over a 2000 rating in correspondence chess and have approximately 1000 in live chess, standard time?
I understand the rules about using the forums to accuse someone as a cheat but does this much difference in rating signal that it is possible that one is cheating?