Hello, I am quite happy to hear that you have started to teach code to your son now. I would advise you to start with Python.This is my personal experience.Python code includes what is needed, no craps.Right.Migrating from one language to other is easy.If he would learn the concepts, then learning another language like C++, Pascal would become the cakewalk for him. You can download Learn Python the Hard Way by Zed A. Shaw.It is the easiest book for python. Link: http://files.meetup.com/18552511/Learn%20Python%20The%20Hard%20Way%203rd%20Edition%20V413HAV.pdf. Buy the paperback after reviewing it.This would be easy. Code.org video is quite good.
Reply, if you have any questions.