a suggestion
What dates around?? How much you looking to pay? I've been to Oz 4 times in last 2 years. Never paid more than €850 return, even in their summer. To do this though you need to be flexable.
From oz to ireland you will have to go:
Oz to Asia or Oz to UAE. Then change plane and fly from asia to europe, then change again and get flight to dublin!
OR with the UAE option Oz to Abu Dabai to Abu Dabai to dublin. But i think its more expensive this way.
Your friend might be better to fly brisbane to sydney, then fly from sydney (brisbane to sydney about €100 return) as more competition/cheaper from sydney.