If you have lost btc to a scammer, then there is no recovery (unless you can report the scammer to law enforcement and they can force the scammer to return it).
He can report to the police or law enforcement if he is living in a country where bitcoin is legal. The country I live in they don't recognize bitcoin as legal and always warn citizens to take responsibility for themselves if they are involved in investing or trading in bitcoin or crypto. The law will not be able to protect you.