Allow me to be of assistance...I am gen Y Aussie, born and bred.
If I were slightly drunk and had just been in a fight and was spewing abuse at someone I was furious at........
I would use f*ckwit, dickhead/cockhead, f*ckstick, f*ck knuckle, wanker, poofta/faggot and all the usuals.
Also, I would most likely begin to make new insults up on the spot such as shit tits, ass clown, cock f*ucker, retarded f*ck monkey....the possibilties are endless.
I would probably drop in a prepared statement that I keep for these rants. I.e. You are a f*ckstain on the fabric of life. That sort of thing.
Truth be told Aussie slang is not very strong in gen Y. We are subject to a torrent of American mass media and it is having an effect. I rarely hear drongo, gallah or boxhead unless it is from gen X/BBer's.
His upbringing would probably influence his language....slightly. If he were from a well to do family he would be slightly less crude.