Some parts of his account stack up quite well.
It seems likely that he landed on Lake Eyre, by his own account because of food poisoning. The suggestion that he walked 70km in 18 hrs seems less credible, but that's fine, maybe he didn't know exactly where he was at each end of the walk, and the true distance is a bit shorter.
On the other hand, the notion that he might have displayed sub-optimal judgement at various points is readily accepted.
The good doctor is certainly a highly-regarded member of the Adelaide medical community.
I've known a lot of doctors who think that their excellent clinical judgement translates into a wider ability to make great decisions. This is a problem with medical training: it teaches people to make decisions, and they get into the habit of doing that, in areas outside their specialty, such as finance, relationships, aviation, etc.