An autopsy was performed, so more will be known when it is finished. Reports from when Mr. Marin was found indicate some scratches. There was no report of a damaged helmet. If there was helmet damage, it likely would have been reported. I think a concussion is unlikely.
Hamster, I do not believe it is reprehensible at all. Are you saying that SAR and first responders should not weigh the odds of a successful rescue against the danger to the rescuers? I'm pretty sure that is a standard part of the equation. I would hope that Sheriffs, Fire Chiefs, heads of SAR, etc. weigh the likelihood of a positive outcome, before sending their charges into harm's way.
Nor do I think it was 20-20 hindsight that Mr. Marin was in mortal danger. The Sheriff had to know at the time that Mr. Marin was in mortal danger at the time. Mrs. Marin described classic symptoms of hypothermia; the difficulty speaking and sluggish thinking are signs of severe hypothermia. That was known at the time to the Sheriff. Also known at the time was Mr. Marin's lack of food, his inappropriate lightweight clothing, the strenuous nature of his route, the weather and the very important fact that they did not know his location.