I am perplexed by his failure to boil enough water. The article says he had several canisters of fuel, which implies some sort of gas (isobutane or similar) stove. These are very efficient at heating water - a one liter pot will reach boiling in about four minutes, a time as good or better than many purifiers. With more than one canister, he had plenty of fuel. The area in which he is hiking is a luxuriant pine/fir forest with abundant fuel, if he had to fall back upon a campfire. If I were to go hiking there tomorrow, I would not bother with a filter

Possibly he felt he had to boil his water for an extended time - which is a fallacy.

The article does not mention which map of the Gila he was carrying. Some are better than others, but any of several topo maps would clearly indicate that the trail down the West Fork back to his car was gently descending, well watered, and easy to follow - very comparable to the Middle Fork trail he had just ascended. Covering the 18 miles would be a modest feat for an adequately motivated hiker. But by that time he was caught up in the throes of dehydration.