Turns out he died a few years ago, but he was well loved by students and faculty alike, says his obit.
I wonder if his family has copies of his lectures. It's a little creepy, listening to them now that I know he's dead, which makes little sense as everyone listens to lots of other recordings of now-dead people and nobody gives it a thought. I guess because he seems so full of life in the tapes? I don't know. I just feel sad that now I can't tell him how much I liked his work.
One moral of this story might be to drop a line to someone you admire, and tell them how you feel, before they're gone.