I enjoyed his appearances in the early seasons of Whose Line Is It Anyway?. Helped set the tone for a series that, eventually, moved on without him, but benefitted greatly while he was there.
How terribly sad. I watched a television documentary about him a couple of years ago. He was struggling with his health, both physically and mentally, and not very well off, but had a very supportive partner who appeared to dote on him and took very good care of him. This really Is very sad news indeed. A great loss.