Around 1999 I saw him at Great Woods in MA (he boasted about being in the forthcoming Blues Brothers 2000 movie) he sat down for most of the show. If not all. (Robert Cray and Tower of Power horns were openers)
I wonder if that is the show that I was thinking of, because it was at Great Woods, and I remember he sat in a chair for most of the show. I guess time really does fly!