I can't say for sure, but if it went forward, and Bob was still able to, I'm sure he would try to appear in some way in any RR sequel. It depends on how bad his disease has progressed at that point. The assumption is he would not be able to, so the script is written without his participation. Once the film is greenlit, they can adapt to include him if he's able. This is all just conjecture, though, at this point. I agree that the company should be concentrating on new IP, but that's a big - read: expensive - gamble, which is why we see so much based on existing.
