Hrm.
I'm just rereading it all, some words are really tough to make out. The last "stirling" image I posted could be a reference to money (maybe). Did Australia use that term back then for money?
Edit:
Definitely a name. He also says his father is really a Raleigh, not Rowley.
I really feel for this guy... my (very very old) father fell and smashed his head a couple of months ago, and was delusional for weeks and weeks (and still in hospital). Their delusions are absolute reality to them and no amount of logic will change what they believe, as they have such strong memories of these nonexistent events. Things they hear get woven into the story, so this Stirling, unless he really does exist, could have been something as simple as him overhearing "he's a sterling fellow" or similiar, and voila! Mr Stirling enters his reality.