G.K. Chesterton, Orthodoxy
John C. Wright, The Iron Chamber of Memory
Those might be heavy lifts. More fun reads that are a straight up gateway drug to a lifetime of reading...
Larry Correia, Monster Hunter International
That book will hook a young man in a hot second. High school reading lists are misery rolled in stupidity. This, rocks. His Dead Six trilogy, written with a no kidding EOD Iraq Vet is lit, and the genesis of the first book was originally posted on WeTheArmed many moons ago.
A little more science fiction bent, written by another veteran of Iraq, Zachary Hill, Sakura, Intellectual Property. It has a heavy metal playlist to go with it.
If he likes a different genre, Terry Pratchett and the Discworld series is fun.
The Book of Five Rings by Musashi is a deep read. It is a mirror, and the more you grow, the deeper it goes.
If he is a gun guy... Jeff Cooper, The Art of the Rifle is enjoyable. As is Ed McGivern's Book of Fast and Fancy Revolver Shooting.
If I didn't hit something, please ask, I am a voracious reader and there is something for everyone.