We recently read the book Brainstorm! The Stories of Twenty American Kid Inventors by Tom Tucker – it was great! The stories will be very inspiring for your son and many spoke about the difficulties they had obtaining patents (as well as the long time it took). I believe there were resources at the end of the book on finding out more about inventing and patents. Check your local library, it will probably have this book. Maybe we’ll see your son on Shark Tank in the future!