He should be proud of what he did. His country called, and he served honorably, in more ways than can be counted. He should also be very very angry.
He is proud. Instead of being angry, he feels sad and powerless. Since the stroke, he tends to feel that way anyhow. He draws strength from things he accomplished when he was able. When those accomplishments are weakened, he feels weakened. He no longer has the strength to go out and fix what other people screw up. It helps him to be able to point to successful endeavors and say “I had a hand in that. I did my part in something lasting and beneficial.” It’s painful to watch it crumble before his eyes.