Looks like his loot table is currently a chance at only dropping an eye.
From what I've read, it seems he should commonly drop shardtooth's flayed skin, and rarely drop the eye, and extremely rarely drop a shard wurm fang.
http://eq.magelo.com/npc/381922
The single post on allakhazam is all I can find about the chance of dropping a rune etched icewurm fang.
At this point, I would simply change the loottable to drop the tunic commonly, eye rarely, and create a different potential drop for the shard wurm fang.
Is there more research somewhere?