I remember some of his posts back in the FGI days. Although I didn't have many interactions with him, he certainly seemed passionate about his teaching. I'm sure he had a positive influence on his students and took enormous joy in seeing them improve their games.
There are so many really, really good golf instructors at the grass roots level that we'll never hear of.
It's not that hard to be Butch Harmon or Sean Foley, who by default have pro level talent golfers to work with already. But the task required of taking a high handicapper and helping him/her become a consistent low-handicap player - that takes an enormous level of dedication and expertise.