I think you have to ask yourself why he picked out this book. You can even try asking him how he heard about it, if you can do it in a curious non-judgmental way.
If you think he chose it because he wanted the team to improve or grow in this area and the title sounded like a good fit, you can probably be more honest with your criticism, especially if you can offer other theories or strategies and recommended the sources you learned them from. In this case, I think he'd care more that his book triggered these discussions than whether it was strictly any good.
But if you think he has read and enjoyed this book himself, or that he saw it advertised on LinkedIn and thought it would be a nice manager thing to get it for everyone, I think you should keep your comments more positive. Tell him about any parts that you did think were good, point out the topics that you're most interested in researching further, tell him about any ideas for the team that were triggered while reading, etc.
I think that defining your idea of a role model could be an interesting long-term project. Ask yourself questions like: What kind of traits do you think a role model should have? What kind of careers or hobbies do you think would attract a person with these traits? What kind of books or documentaries can you find that will introduce you to people like this? What are the things they do that you want to emulate? What other traits do they have that you didn't initially consider? Where might you find people like this in your real life?
You might not find a single perfect role model to look up to, but hopefully you'll learn more about what kind of person you want to be.