Damn that sucks
Doubt you will use PayPal again
No PayPal will be the saving grace here ... If he had done a bank transfer to the seller he would be totally out of luck.
With PayPal he is safe and even if they don't refund (they will) his CC company can do a 'trace-back' and will reimburse. However you may have to report the seller to the police and get a crime iD when dealing with your CC company and keep a copy of all communication between yourself and the seller until the point they stopped communicating.
I've had to go that route in the past too. It's a little longer than a PayPal resolution case but you still end up getting your money back.
If anything it's more a case of being turned off swappa in the future.