He had some rough notes, a few important scenes written out, but the man was diagnosed with a terminal disease. Despite best efforts, he didn’t make it to the finish line.

I feel like you’re downplaying it a bit. Robert Jordan spent the last year of his life dictating the final novel (which was ultimately split into 3 novels because it was so large) to his editor, who was also his wife and a stenographer, including detailed notes of the world itself so that someone could finish the series after him. It was much much more than some rough notes.