You beat me to it. I read about that, earlier today, and intended to post that this evening. I wonder who he is saluting. God? St. Peter? Or whoever gave him his orders?
He's saluting the officer awarding the Purple Heart to him. Traditional and customary. What's amazing is that the salute is from a guy that was assumed to be unconscious.
It is "My Opinion" that he was Saluting his Commanding Officer that had just awarded him the "Purple Heart" and by doing so acknowledged the receipt of that Medal..... ..... and on Another NOTE:. I Salute the Army Captain who was awarded the "Medal of Honor" yesterday... as a Great Example of a Unit Commander, showing his love for his Troops. That Soldier he kissed was his First Sargent, wounded twice in the battle, that his Superiors refused to send Reinforcements, or Air Cover, when called upon by the Captain... There is "No greater Bond in the Army than that, between a Unit Commander and his First Sargent".... My Opinion... YMMV...