Not sure why they were given up on when temperatures were HIGH.
Cold, sure, but high temps shortening survival? In the woods where there is shade? and likely water?
If I read the article right it was only 6 days.
Even with shade, 40C (104F) is well into heat stroke territory. Thankfully, the couple had enough sense to stay put, in a lean to, near a water supply.
There were meadows in the search area where aircraft might have spotted lost human figures, but Moynan and Carmody stuck to the woods, where they built a temporary shelter and stayed close to a stream for water
Shades of Gary Paulsen's "Hatchet"