Yury, I've not seen a cause of death. But they did say he was found on the southwest slope of Whitney about 12,500 elevation.
So that puts it
about here. "southwest slope" doesn't mean exactly 225 degrees bearing.
That night was not that cold.
I suspect that he had some underlying health conditions.
Haha, true that it wasn't notably cold, but the man in question was without a pack, in his twilight years, likely underfed and dehydrated, and you can go hypothermic in 50 degree weather.
I developed hypothermia sleeping un-swathed in 50 degree weather. Imagine a 68 y.o. man, alone, unprepared, likely dehydrated, and definitely exhausted.
If he injured himself and couldn't move, that could easily have exacerbated the situation.