I hadn't worked with him and unfortunately only know his name from others speaking of
his work. As you heard I believe he had one of the largest/complete collections of cp/m
out there. He seemed like the go to guy if there was an image needed. From what I
understand there wasn't an online archive of it so he just had the collection in some
form offline (probably due to copyrights and liability) but he'd offer the image upon
request.
I thought Curtis on the vintage-computer forums had also begun creating cp/m images after
Don's collection was deemed "lost". I don't recall if he was in touch
with the family as well.
These are just my passer by views though. I'm sure others here knew him better than my
speculations.