This is sad news. He was deeply influential and at the same time a somewhat obscure author. At least, in my experience, he didn’t have the name recognition other - dare I say lesser - authors had.
One lesson I learned as a young person from reading A Fire Upon the Deep was to never believe anything just because it was on the internet. That alone makes his legacy worth remembering.
He used to go to library conferences somewhat regulary. I meet him a few times and he was always extremely nice. Laste time I saw him was pre covid. He was looking pretty frail even then but still signing books for a line of fans.