How do I find a book for a man who only loves Craigslist, Jesus, and Keto?

​Hey everyone, I’m stuck with a specific challenge.
I'm looking for a gift for "Gary," a 40-year-old engineer. He’s the definition of "set in his ways."
He’s single, eats strictly keto, and spends his weekends either on his property fixing tractors, tillers, and heavy machinery he buys off Marketplace and Craigslist or purchasing more (typically the latter).
There is not a spare moment that is not spent on browsing marketplace and Craigslist.
​He’s deeply involved in his church (men’s softball, weekly meetings, etc.).

ANY book that sounds like something for him would be great! It doesn't need a hidden meaning, I just want to share my love of books and hopefully i can find something he would enjoy reading.

​Definitely bonus points for anything that:

​Speaks his language: Something an engineer or a tinkerer would actually respect.

​Softens the edges: I want him to see that "free-spirited" or non-religious people aren't "bad" or "lesser."
I want him to understand that people who prioritize things differently in life are just as important as his church community.
​He loves baseball, football, and old machines. He "has it all" already.
Any "gateway" books that might help a very rigid guy broaden his horizons without feeling like I’m forcing a sermon or a political manifesto on him?

I do not have any bad intentions with this, it's important for me to find something to connect over and I have tried for 4 years now to find common ground.

Thank you for any and all ideas you send my way!