I tried to get my grandfather to talk for years about his service in WWII. He had a metal from the invasion of Africa. He never wanted to talk about it.
The one time he said "God, I remember trying to shoot down German plains with a 90mm cannon................" Then he just stared off into space for a moment with this vacant look on his face, grimaced, shook his head as if to shake the image from his mind, and then changed the subject. I never tried to get him to talk about it again. I could see the things he had to do haunted him still.
It's a real shame though, because every time we lose a vet we lose a bit of real history. No idea if it was a 90mm or a 30mm or whatever kind of cannon, as I'm not that familiar with WWII artillery, but I don't think I'll ever forget the look on his face.