Dave
What you should do immediately before he dies, for both him and his family, is get his military records. These are available on line. Many have been digitalised but if they have not, they will quickly be copied on request. His records should make great reading.
Start here:
http://www.naa.gov.au/collection/exp...army-wwii.aspx
What they also will do is jog his memory to remind him of people and places he has forgotten and as he has reached the stage of not buying ripe bananas someone should sit with him with a voice recorder and ask questions and let him run.
As an 8th Division man it means he was early into the war so must be looking at reaching his century very soon.
So easy to do but it will be lost forever in the blink of an eye. Make the effort to suggest all this to his family - soon!
Lang