This is really a simple fight if you set up your specs right...Respec to full defensive in WIS and full HP and the taunt in STR.
Park your pet in front of the named, and then place yourselve next to the brazier so that you can TAB target any elementals. Then just stand there and examine the brazier to start the event.
Send in your pet to attack using an initial buffing of Blazing Presence, then just back him off. (You can have the pet keep attacking, but back him off when he hits half health, at which point his regen will outdo any damage the named does to him) Spam the pet taunt on the named EVERY time it's up...and hit the ol' Tab key every time he brings an elemental to life. By just standing here, you don't have to worry about missing one of the elementals...which are fine if you miss 1, but if you get hit by the air, you're done.
Keep doing this until he's dead...the fire and earth elementals are enough to kill him. Whatever you do, don't cast on the named though since this won't work if you get aggro and die. It doesn't take long to do really, and is pretty much an Easy button for this last fight.