Ok to start off, I've only ever done this on a private server so im not sure if it acctuelly works in Retail, If it doesnt then atleast you can do it in a private server
Ok... you can do this 2 ways.
1. be a rogue <-- easyer
2. be any class (tank works best) with someone to res you
items required: flash powder, seed to res (if druid)
1)
First of all you if your doing the second choice (with resser) then keep the resser near the platform mother stands on without agroing her.
get your tank to agro mother and run instantly past the doorway on the right and before you die, get the resser to follow you past the door so.
Mother will obviously kill you. res up and buff up.
2) start running up to Illidan (only the tank, Resser stay next to where you the tank died)
When you get to illidan, walk up to him slowly untill you just about agro him.
now when you agro him run back to mother but make sure you dont run too far ahead of Illidan so hes about 2 seconds behind you then run around Mother's platform trying not to agro her.
3) When you get to the south side of mother's platform (where you would normally come from to attack mother on retail or w/e)
get on her left side without agroing her again, and obviously Illidan wont follow the waypoints you just done to get there, he will run stright through past mother.
4) Mother should start attacking illidan taking the agro (you might of died from Illidan attacking you or may not depending on how well you do this)
If you die res up and Illidan and Mother should be fighting eachother.
quick edit, forgot to explain how to do it with a rogue
When you get to Mother with Illidan following you, simply run round Mother without agroing her untill illidan is near you and mother should be chasing illidan while illidan is chasing you, let mother attack illidan and then vanish, If all goes well mother and Illidan will be fighting
Now you can choose: kill mother or kill Illidan?
who ever you choose just start the DPS
Good luck
But also im not too sure if it still works, Its an old trick but i doubt its been fixed.
Flame away
:wave::wave::wave: