Did he leave or was he shown the door, as in house of four doors...
I believe Patrick did sue the Moodys for firing him, which probably went nowhere. I was a fan of Patrick, I actually saw him live doing a solo piano tour way back in the '90's, I'm thinking '94 or so. SUCH a virtuoso! "Story of I" was & remains a great favorite, and his first post-Yes album "Out in the Sun" is a career high point to my ears, and worth seeking out. The 1973 "Refugee" album, Patrick with ex-Nice guys Lee Jackson & Brian Davison is also a really impressive showcase for Moraz' keyboard & songwriting chops.
I give full credit to the Moodys for blazing the trail for Mellotron prog, and "Days of Future Past" is rightly acclaimed as an early bloom in the progressive/psychedelic garden. I must say, though, I'm just not feelin' it with most of their discography. One lost to memory critic captured my reservations nicely when he dismissed their albums as juvenalia, the sort of music that seemed profound when you were in junior high, but lost its luster quickly as new & better bands captured our attention & favor. Of course, as always, no one's WRONG for liking them now.
A local & lifetime prog/quad friend has been gathering the new & VERY lavish 5.1 mixes of the Moodies' prime era early '70's LP's as they emerge from the fog momentarily, and I definitely admire the archival effort to gather, remaster & offer such definitive editions for fans' enjoyment now, and for general posterity. But I wouldn't buy them for myself. As all us quad fans know, most of these '70's Threshold label albums did get released in quad 8-track, but NEVER on any quad LP format. I suspect the new 5.1 mixes are completely new & different from those original quad mixes.
My dream multichannel reissue would be any of Focus' knockout 1970's catalogue, GRT quad 8-tracks were made of "Moving Waves" & "Live at the Rainbow," but again, never any LP version. I'd be thrilled to get a new 5.1 or Atmos reworking of "Moving Waves," and "Hamburger Concerto" would also be an OUTSTANDING multi-channel reissue, or certainly "Focus 3", which never had any quad release.