I think I read in his blog somewhere that he had notes on how he wanted the story to end. There was even talk back then about have a ghost writer if the worst happened, because he knew that he was terminal quite a while ago.
The book he was writing was supposed to be the last. He was determined to get it finished before he died, but he did not make it. He jokingly stated that this would be the last book even if it had to be 30,000 pages.
Anyway, I am crossing my fingers on the ghost writer thing.