I have, on several occasions been reading a series of books by an author who either died, or just quit writing.
Some of these were picked up either by "loved ones" or, more often, by the dissatisfied publishers and "completed".
Not once has the result been satisfying to me as a fan of the original. I have heard others make this argument about"worthy causes", but it all boils down to paying a hack to finish a work of art. Should we now have "artists" complete the unfinished works of all histories great thinkers, painters, writers or engineers? Should the sketches and scribblings of the great painters of the past be "completed" and then marketed? How soon before we have works in our museums and galleries painted by Rembrandt, featuring Larry Smith? I have nothing against Larry, or any other artist trying to make a name for themselves, but don't mess with the best. A great example of this is the recent fantasy series "The Wheel Of Time" by Robert Jordan (and Brandon Sanderson). An epic story with millions of fans who waited desperately for each new book in the chain. And then Robert Jordan died. With the story mostly, but not completely, finished. So his widow and publisher decided to hire a second rate hack to complete one of the greatest stories ever told. And it flopped. The story could not be finished in anything like a satisfying manner, because so much of the story existed only within the mind of Robert Jordan. In spite of copious notes and pre-plot scripting left behind by the author, who knew he was dying.
If it could not work in a situation where all parties were in agreement and cooperating, how could it possibly work here, where the author has left no such detailed mapping of the future of the story, AND has expressed his desire for his writing career to die with him?
And, please, don't tell me how you have decided that the unfinished works of Terry Pratchet are going to change the outcomes of Alzheimer's research. The man sold eighty-five million books in his lifetime. I'm sure his heirs/ estate could afford to give just as much as the sale of the unfinished books would make. It is just another form of disingenuous marketing.
I say leave well enough alone. Honor the man for his achievements in life, but do not diminish him by marketing his corpse.
Just my thoughts.
Be well.