Each of us handle situations differently. He believed he was gravely ill.
Anyone who has had food poisoning will know just how it makes you feel. It can disable you very quickly, & an attack while flying would not be nice. Probably better that he did land, rather than become incapacitated & crash.
Under the assumption he flies for work, I would personally be admiring him for operating an aircraft and servicing patients in outback locations rather than a big city CBD.
He is a nephrology (kidney) specialist at the Royal Adelaide Hospital (RAH) - I don't think he flies for work.
DF.