The Corel suite of design products were his tools of choice, both in industry and when he became a teacher. To him, CorelDRAW was a leading product, and even now we've got a few old CD's of Corel products lying around the house. It was also amazing to me how someone with limited computer knowledge can use a software tool so well. He still double-clicks links on web pages, but he can create a full building plan with ease in CorelDRAW, so they must've been doing something right!
Despite being long retired, he'll occasionally work part-time when needed, and when he needed to cover for a few months I helped him get the latest Corel suite, and he really struggled to get on with it. I remember playing with it as a kid, and feeling the same way when I tried it out, so to get his work done I had to hunt down an old copy of CorelDRAW.
Corel seems to be a shadow of what it once was, and its software reflects that, so hopefully this acquisition results in better software for the future.