Does he recover 1 fatigue for each wound received (1 for 1) or if he is hit by a monster (and say takes 2+ wounds) does he still only get 1 fatigue (as he was wounded)? If its the latter, I assume that it is not turn based, and as such if another monster hit him (causing wounds) he would again recover a fatigue.

It´s the latter and you are assuming correctly - every "set" of wounds (even from traps) recover one fatigue for him. Mind that he actually has to take a wound, so preventing wounds via Ghost armor or the like won´t count.

Further on that, Mordrog is in my SoB campaign and I have the count with Bloodsuckers, so my Razorwings have Leech. Because the fatigue drain from Leech is part of taking wounds, we ruled that he loses the fatigue, then gets one back for being wounded.