Either he is a hacker, or he has just prefarmed. With that many tokens, he has been accumulating tokens for 4 days and 3hr., and probably just joined your co-op. If this situation hasn't happened, he may be time cheating.
I think IdleCarl is right--he just prefarmed (started the contract and played for several days before joining your co-op). That's legit. Now, if you see someone with more tokens than can possibly be earned for the entire length of the contract, then you can be sure you have a cheater.