Michael3,
Yes, what was Andy Andrews remembering as he sat, head bowed, on the flight deck?
It must have tough on you as a boy, growing up with an emotionally  "closed off" father.  It's  good you now understand the emotional burden he was carrying all those years-
There was the loss of all his buddies,  survivors' guilt, the horrible shock of escaping a damaged plane, surviving on the ground....
Something else that's rarely discussed though it affected many bomber crews- sometimes these  men  had to make runs they didn't like, as they knew they'd  be hitting civilians below--Dresden was a sad example.
Again, I'd encourage you to look for that excellent book on WWII B-17s by  a local author, Michael Pungercar, "The Promise Kept."  Like you, he was the son of a WWII Flying Fortress crewman, and this book on his father's  incredible experience fulfilled a promise Pungercar made to honor his father's service.  I think this book would help you understand your own father better, Michael.