Matt, do you know if the man in question stayed in Australia or returned to Turkey?
Are there any relatives or friends who may have known him?
I am fairly sure he returned to Turkey and I doubt he had any other family here.
I can't be sure of this, but my mother believed he wasn't a citizen, though she said she was not 100% sure of that.
The only other DNA matches seem to trace their history back to Bulgaria, but are of Turkish descent as well and they are quite distant matches and have yet to turn up anything meaningful in regards to tracing this identity.