I only recently heard of his death, even though it's been a few years already. However, I was really surprised to learn the true reason for him leaving the show after the first season: He was suffering from paranoid delusions, which only became known after his death because O'Hare had asked JMS to make it public after he had died.

https://en.wikipedia.org/wiki/Michael_O%27Hare#Illness_and_death

RIP

In the US, Babylon 5 is available for streaming for free on Go90, no commercials either:
https://www.go90.com/shows/babylon5

Why is it that only at moments like these I'm reminded at how long it's been since I've rewatched Babylon 5.

Last time, when Jerry Doyle died, I managed to rewatch the first 2 seasons before life got in the way. Rest in peace, Stephen Furst. It's so rare when secondary characters improve a show, but you were one of them. You deserved to become Emperor.