There is a pre req quest you must do to see him that isn't on the guide. I think it's this one http://eq2.wikia.com/wiki/A_Vicious_Tongue It's a one off quest in the centre of the zone and after that you can see Ghawg. I know because I was 2 boxing and one could see and one couldn't. After going back to turn in this quest (I think it was this one) on the toon that couldn't see him he was there.