Sorry to hear the news.
John and I got to know each other a number of years ago, although I don't recall just how it happened. Suffice it to say that John owned a Wang word processor that he bought from Los Alamos National Laboratory about the time he left the lab and started his own business.
John was an industrial respiratory expert; his business was mainly concerned with providing expert testimony for court cases. At any rate, I was writing specifications for the purchase of fire engines, and started using the Wang.
While using the Wang, I found out that John was an expert in respiratory protection, so I persuaded him to join the Eldorado Fire and Rescue Service (the second volunteer department I had started); once he learned how the fire service used self-contained breathing apparatus, John took over the training for that aspect of firefighter training.
While John was certainly an expert in his profession, he was anything but an expert in the use of computers, unless being an expert in that area meant finding new and clever ways to totally foul up one's computer. I spent more than a few hours at his house restoring his computer's ability to breathe....