Hello there
Well he may very well have been invalided out.
You could try the white pages on line.
http://www.whitepages.com.au/wp/resSearch.dothis is a carter in tarragindi not the same street though
Electoral Rolls aren't on line
may be we might find his fathers Ralph? death
what is his parents names and his a birth year.
you could also get his service record the the NAA
it may give you more clues it will at least tell you why he left the service so early.
You could also try war graves commission if he has died he would have been entitled to a plaque from war graves so they may have his details on file I got my grandad burial place this way.
just mulling over suggestions
regards jenn