You just need the email he uses for PayPal.
He is flagged after the MV issue so a few complaints can hurt him.
I think you can call PayPal anonymously and report that you have seen videos of a guy that makes claims that PayPal steals his money and boasts about getting money back while showing that the item is in working order.
I am fairly certain you just need to call and get directed to the fraud department and they will be happy to take all the info and look into an account.
I am not positive they will do anything but I think they would perk up when they hear it is not his credit card he is using.
Hopefully someone else will do this. I mean I hope someone will do this.