Wow, that pic of your grandpa looks like it was taken prior to jumping into Normandy, the night of June 5/6, 1944. He is in full combat gear and has the much-hated M-36 musette bag, most of which blew off when they exited their C-47s. If this had been taken prior to jumping during Operation Market-Garden (Armhem, Holland) he likely would not have been carrying one of those.

What a bad-ass, no wonder you learned so much from him!