Confirmed he does spawn at +465, +330. This is the room before entering the area under the bridge when entering from the city.
To get to this spot, drop off first bridge in from Thurgadin and zone into Icewell Keep, then fight your way all the way north as there are a mixture of mobs that can and can't see through invisibility.
When you come to the first and only turn, keep going north (right). The correct room is at the loc provided above. There are 3 "a Coldain skeleton" which spawn next to him or his PH (two on the right, one on the left). There is an untargetable pile of bones before entering the room, I've found this pile of bones a safe spot to camp on while you wait for respawns.
His PH is the single "an avalanche golem " in the middle. The skeletons will likely agro when you engage. Keep them killed if you feel like it, but they have a faster respawn time (21 minutes 30 seconds) than the PH (48 minutes and 13 seconds).
Summons and runs at low HP.