A very sad development. So sorry for his family and hiking friends.
All I can say is Wow! They found his pack on the n-nw side of Whitney, above where he left his friends, and then they have found his body, a mile southwest, at the 12,500' elevation. That is not too far (a few hundred meters) from the JMT (John Muir Trail) where it climbs south and east from Guitar Lake.
It is certainly puzzling how he got there.
