Killed him tonight. Very easy for what the game takes him as. Max hit was around 1150. He was actually a very common pop before and after I got the quest.
APPOX. Spawn location is +6081, +32.5 WEST side of Water fall. He will roam, but kill that PH sit near that location and kill any mob that moves near that location thats his PH.
nothing you can do but rack up EXP while waiting for him to spawn... took us 4 hours and 25 aa's to get him to spawn just kept the whole place cleared i dont even think it has a PH
Yeah, he spawns in the west corner by the tents and to the west of the waterfall. To be honest, I'm not sure he has a specific PHer though except that the corner needs cleared. I had just recently cleared that corner and WAY BEFORE it was time for respawn over there, he popped.
Every time I have seen him spawn, it was from one of the guys walking around the pool farther to the back.. There are three or so of them though, so which one is his PH I couldn't tell you. I have seen him up 4 or 5 times though, so I am positive his PH is only the treants by the pool.
By the way, he does not summon, hits for the same as a tottering, and has the same hp. Very easy solo, regardless of what the fellow offering the quest says.