Update -
He responded to my email letting him know that the money is still in my account. He said "my bank told me that they was no account number and the check has been returned to me, I figured I had been the victim of internet fraud, please advise".
Ummm, okay. The cheque is a normal cheque. Printed off by my local branch of the bank I WORK FOR.
He never reached out to me or anything. Sounds like his bank didn't know how to read a Canadian cheque (?) and he never got around to reaching out to me. I will put a stop payment on the cheque and do an email money transfer for something. Now I'm scared that if I do a money order, that I might be SOL if something like this happens again, if the money order gets lost in transit etc...
At any rate, I will figure something out and get him his money.
The only reason I sent a cheque in the first place was because he said doesn't do paypal.