You might search for Everquest forums and post his obituary there--assuming you know his user names:
https://www.google.com/search?client=firefox-b-1-d&q=EverQue...
https://www.google.com/search?client=firefox-b-1-d&q=EverQue...
Discourse for online games these days is mainly done via Discord, however. So there's a good chance you won't find them on the forums.