He was in great shape at OSH '09 - did a number of book signings and a talk in the war bird area. I shook his hand, bought his book and exchanged a few words about Joachim Marseille. Sounds like he had a stroke or heart attack and died two days later - now that's the way to go.
I too bought his book and had him sign it at OSH. It was one of the highlights of the show for me. He looked very good (and 91 to boot). After as many
crash landings he had during WWII it is a wonder.