I just discovered a book called "The Secret Behind 'The Rape of Nanking': A Spiritual Confession by Iris Chang" by Ryuho Okawa. A small bit of background: Iris Chang's impressive and well-researched account of the massacre and ill-treatment of thousands (true numbers unknown) of Chinese civilians at the hands of Japanese soldiers during WWII in the city of Nanjing is compellingly documented in a book called "The Rape of Nanking", published in 1997. Because of the depraved picture it paints of the Japanese military, many Japanese nationalists state the claims in the book are exaggerated or outright false, despite the evidence and much of the rest of the world agreeing on the details of Chang's account. She died by suicide in 2004.
Enter "The Secret Behind...", a book written by Ryuho Okawa who wrote a book to introduce doubt about the facts found in Chang's account. To do this in a way that seems credible, they claim to be "summoning the spirit of Iris Chang from the spirit world." More from the back cover: "Regardless of whether or not you believe in a spiritual message phenomenon, as an individual human being, you cannot remain unmoved by her tears of apology [for writing "The Rape of Nanking"] and the truth in her plea." Apparently her spirit, as channeled (?) by Okawa, wants to apologize for her damning account.
So my questions: In publishing something that claims a dead person said something clearly contradictory to their life's work, is Ryuho Okawa exposing themself to legal repercussions from anyone? Would it change if Iris Chang were alive? Is there a time limit for protecting one's reputation from "ghost-versions" of oneself saying contradictory things?