I never knew that Paypal FF is irreversible. I am sorry for your lose. You should not send FF first neither the scammer too. When a user do not have much rep here, it's always advisable to use escrow.
Archive:
http://archive.is/xnrWNI will tag the guy and I hope he leaves this kind of scamming profession.
Edit:
Tagged
PayPal friends/family is not irreversible, however most of the time once a payment is sent, it cannot be reversed. In certain situations, for example when a payment is sent from a new country/IP that makes it obvious that the payment was not authorized by the account owner, only then will PayPal consider reversing it.