I’d say something like: Thanks for the message! I can gladly send you a copy for you and/or your team.
But out of curiosity, how did you find out about the book? What type of challenges are you having right now?
And that might transition to a “coaching call” where he would get a taste of the insights you can give him and im sure that good things can come after that.
One of the most common messages I receive is: “My videos/podcast/posts/events are killin’ it right now! I get XYZ,000 views/downloads/impressions/attendees every month. Can you help find brands to sponsor me?”
Now, on the surface, this is a reasonable question.