Technically we don't know if Cbob has been alive / contributing since he basically quit in FET's love route citing depression or what I suspect, boredom. He came back for a little bit with their last poll for dragon prince but when it lost to Kim Possible it's been radio silence.
Marty's been given a choice. Keep skeleton updating the game (and now 18titans since that project got some support the first time Cbob went afk) and 'legally' keep drawing an income from MITY or go off on his own and probably not make anything as well received as FET and have to draw furry unbirthing vore ntr these days.
I can't speak for 18titans but Slave Epilogue's writing has actually been great. Pacing of updates is kinda shit but the dialogue and jokes have been as good as Cbob's back during the original book 4 slave route. The practice from Love Epilogue has seemed to help. And the premise is probably easier to get in (Tenzin has seemed to stay a pervert who watches his sister shower and potentially has kept fucking his underage daughter who herself was basically a mini succubus just like the mother he's married to.
actually cBob suffered from a mental breakdown, and ran into a writer's blockade while still trying to recover, something along that line. a wide number of medications actually do that, brain gets mush and you can't keep going on with something that relies heavily on imagination. that was back when they went and closed funding, so wouldn't call it 'legally' anything really; those quotes imo don't belong there. Marty did what he could and improved alot, as time went on, but in some parts you can tell a certain difference in the dialogues. then, when they declared the project FET 'final', Marty as the restless type of artist is still continuing because for him, it still doesn't feel 'just right' so to speak.
the whole 18titans however are Marty's side project. that's all him. now with MiTy (as in, both of them as team) not having a new project in the works, he splits his time working on even more 'final touches' for FET, and his solo side project 18titats.
i guess whenever they decide on something new, together as a team, well.. cBob won't likely be very active on their patreon still. he wasn't as much active with people as Marty is, throughout the years, even back when i still was on Patreon.