Aw man, that's sad.
He did some pretty great work outside of SST too: he did an HBO special called WHITE WASH, about a little black girl who goes into hiding after she's attacked by a gang of white street toughs, who paint her face white, and he also animated all of the flashback sequences in the last episode of COURAGE THE COWARDLY DOG. Matter of fact, he and John Dilworth were big fans of each other's work.