Well he is going to find out that his 'books' in the US are essentially in the public domain and are un-copyrightable due to this ruling: [0]
Human authorship is required for obtaining copyright for the books in the US and not when an AI has done the work entirely or has done the majority of the work in both generated text and images and especially when they are crediting an AI as the author or co-author.
[0] https://www.copyright.gov/rulings-filings/review-board/docs/...