what i would do is get together with the other people who were scammed
secondly email and try and talk to the people whom he bought from before and whom he sold to. doing this see if they can go in their paypal history, cuz that seems like his method of payment, and see if they can get his addy, real email, name, etc..........

also whats weird is that he got positive feedback after like 10 negatives....so contact some people