To answer you question first: I believe that is too young as others have stated.
Second: My interest in Texas History really took off when I started reading some of the J Frank Dobie books my step dad had. Most focus on a single subject or part of the history and some just use a shotgun approach about many different things.His writing is easy to follow and usually very entertaining.He tells many stories about things that make us Texans proud to be from Texas.I don't remember anything in any of his books that I would consider inappropriate for a 10 year old.
His List of works
- Weather Wisdom of the Texas-Mexican Border. 1923 Ebook
- A Vaquero of the Brush Country. Dallas: by John Young and J. Frank Dobie, The Southwest Press. 1929.
- Coronado's Children. Dallas: The Southwest Press. 1930.
- On the Open Range. Dallas: The Southwest Press. 1931.
- Tongues of the Monte. Garden City, N.Y.: Doubleday. 1935.
- The Flavor of Texas. Dallas: Dealey and Lowe. 1936.
- Tales of the Mustang. Dallas: Rein Co. for The Book Club of Texas. 1936.
- Apache Gold & Yaqui Silver. Boston: Little, Brown. 1939.
- John C. Duval. First Texas Man of Letters. Dallas: Southwest Review. 1939.
- The Roadrunner in Fact and Folk-lore. 1939
- The Longhorns. Boston: Little, Brown and Co. 1941.
- Guide to Life and Literature of the Southwest. Austin: U.T. Press. 1943.
- A Texan in England. Boston: Little, Brown. 1945.
- The Seven Mustangs. Address delivered at the unveiling of the monument, May 31, 1948, University of Texas, Austin. The Adams Publications, Austin, Texas,1948.
- The Voice of the Coyote. Boston: Little, Brown. 1949. Paperback edition, University of Nebraska Press, 1961.
- The Ben Lilly Legend. Boston: Little, Brown. 1950.
- The Mustangs. Boston: Little, Brown. 1952.
- Tales of Old Time Texas. Boston: Little, Brown & Co. 1955.
- Up the Trail From Texas. N.Y.: Random House. 1955.
- I'll Tell You a Tale. Boston: Little, Brown & Co. 1960.
- Cow People. Boston: Little, Brown. 1964.
- Some Part of Myself. Boston: Little, Brown. 1967.
- Rattlesnakes. Boston: Little, Brown & Co. 1965.
- Out of the Old Rock. Boston: Little, Brown & Co. 1972.
- Prefaces. Boston: Little, Brown. 1975.
- Wild and Wily Range Animals. Flagstaff: Northland Press. 1980.
This is not a comprehensive list as he was president of the Texas Folklore Society which published items quarterly. Many of those have the best information and stories you can find anywhere.
I believe Elmer Kelton was mentioned above. He has a few good books, but his are more fiction based than Dobie's. Good reading but not always factual. Exception would be "The Time It Never Rained". I have given this book to several old-timers who lived through the drought of the 1950s. They said that it described what it was like better than they could tell the story.
If his fascination is mostly about the Indians, WW Newcombe Jr wrote a very comprehensive book about all of the Indians in Texas. It might be a little above his reading level, but not much. You should read it before him but I don't remember anything inappropriate for his age.
I usually peruse the Texana section at Half Price books when I get to one. There's usually something there I haven't read that piques my interest and is usually just a few bucks.
I will check my library when I get home in a couple of weeks to see if there's something I forgot.
These are the times to develop things that will become lifelong values for your son. I think it's great he wants to learn about other(older) cultures. There are many lessons there to be learned.
In youth we learn, in age we understand.
Marie von Ebner-Eschenbach (1830-1916)
Writer
Edmund Burke (1729-1797) said "Those who don't know history are destined to repeat it."
Learn from the mistakes of others. You can't live long enough to make them all yourself.
I’ve seen them play since way back when,
And they’ve always had the grit;
I’ve seen ‘em lose and I’ve seen ‘em win,
But I’ve never seen ‘em quit.