Your post #30 very strongly implied that Shin wrote the book.
The article explains that he didn’t.
Simple.
As I understood the article, the book was transcribed from what Shin said, so it’s hard to tease out who is responsible for what in a collaborative project like that. But once again, what difference does it make who wrote it? The point is that having a smooth literary style is not important. The revelations in the story make it valuable, not a snappy popular style.