I only met him once at a conference, probably around 2010 or so, we had a very brief conversation during a discussion at a talk, I think he was asking how many integrals SymPy can do from some test suite (I forgot which one), but I remember it could do about half back then and he said that’s very good. He was very nice.
I think he created MATLAB while he was at UNM here in Albuquerque, NM in the 1970s. We have a thread about how to compile the original version (in Fortran!) here: Compiling the original Matlab.