This news came to me last week, but I thought I'd wait to write here until I could link to a full obituary. I never had Don as a teacher at Germantown Friends, but he was an extremely close friend of my mother's - they met in graduate school at Penn in the 1960s, and it was in fact on Don's urging that my mother applied for a position at GFS, where she proceeded to have a fantastic thirty-plus-year career (my brothers and I all went there basically as scholarship kids on the strength of her position, so we really have a lot to be grateful for!).
I particularly associate Don with the amazing four-hands piano canon that he and my mother worked up from time to time for public appearances (Faure, Poulenc, etc.). Also, ragtime as per below! But he was a very good friend to our family over a huge span of years - I remember him visiting us when we were still living in the suburbs of Wilmington, Delaware (mid-1970s) bearing implausible and delightful gifts: Chuckles candy, which we rather despised (especially the liquorice one) but found magically intriguing regardless; Halloween masks (Wonder Woman for me, Spiderman and Batman for my brothers - in those days as you probably know the younguns had a much more modest influx of new things into the home, so this was thrilling); and one Easter, a present that became one of my utter favorites, and is now in the fond possession of my niece GG: a pink plush rabbit, with revolting and yet endearing big pink googly eyes, subsequently known to me as "Mr. Bacon" (the resemblance to the cured meat was unmistakable) and second only to stuffed chimpanzee "Jim" in my youthful affections.
(Unless I am misremembering, it was also Don - who had a huge, eclectic and fairly risque collection of VHS cassettes - who introduced me and my brothers some years after that to the unforgettable Videodrome!)
My classmate Adam Goodheart explains more effectively than I can how meaningful it was when Don came out at the commencement exercises at the Arch Street Meetinghouse in front of students, parents and grandparents (scroll down to the comments): as Adam says, it is easy to forget how homophobic even a liberal east-coast independent school in the 1980s was likely to be, and how taboo it was for teachers or students to reveal that they were gay.
This Youtube snippet gives much of the flavor and appeal of Don's presentation style as well as his piano-playing. He had the longest, most multi-jointed fingers I have ever seen on a pianist!