I knew I recognized the name, because I get emails with his name on them all the time. I've bought from KSF a few times and I know people speak very highly of him. Certainly a loss for the knife community. I can't find any official announcement from the website, but his daughter posted the information on her Instagram account. I didn't think it was in good taste to screenshot the post.
I just saw this a few minutes ago. Somebody posted it on the Spyderco closed group on Facebook. Rest easy.
Terrible news. Derrick was always an excellent person to deal with, in my experience. All the best to his family.
Very sad news. I bought many knives from him over the years and always had positive interactions with him. Definitely a loss to the community.