I recommend Chess fundamentals by JR Capablanca:
https://www.amazon.com/Chess-Fundamentals-Jose-Raul-Capablanca/dp/1627554637
Just to make a friendly suggestion, I suggest the book from World Champion Jose Raul Casablanca, The Chess Fundamentals. Its probably the best beginner book that you can go over with your son. Check it out: https://www.chess.com/blog/yucca/chess-fundamentals-by-capablanca
http://www.amazon.com/Chess-Fundamentals-Jose-Raul-Capablanca/dp/1627554637