I wouldn't worry too much about the language, try to link it to something they enjoy. If your son enjoys video games teach them javascript/html5 and let them bu

I wouldn't worry too much about the language, try to link it to something they enjoy. If your son enjoys video games teach them javascript/html5 and let them build in-browser games they can easily show off to their friends. If your son likes to tinker with physical things, do an arduino project with him.