On the topic of unfinished novels
Only occasionally, the executors of an estate find the right collaborator to finish an author's work in progress, and only when they are reasonably certain of a good outcome should they proceed. One of my other favorite authors, Dorothy L. Sayers, had an unfinished Lord Peter Wimsey/Harriet Vane novel that took half a century to find its collaborator in Jill Paton Walsh. The novel lacks some of the classical scholarship of Sayers, but the characters are given the chance to breathe one more time (with a nice afterword as to all their fates during and after WWII). A worthy addition to that series, Thrones, Dominations.