I flatly asked dad, "what are you thinking about." He turned and looked at me a moment, then waved his hand around the missing skull.
"I don't like how this feels" and then returned to looking out the window.
Mom and I stopped at Safeway on the way home. She told me similar that came from him during the day. Something to the affect of "My head hurts when i try to think." I like to think he's just re-wiring himself, and it's a bit painful.