If you go back through some of my Fundamentals videos, pay close attention to what I say to the student as to how to get the best tone, how to make the chord changes quick and smooth, etc.

Listen for the 'teaching' in the videos. What am I suggesting you make sure to do? What am I suggesting you make sure to watch out for? To avoid?

Then, you may be able to use those teachings to coach your son.

Notice little things he may or may not be doing in his technique that are impeding good tone, etc.

Teach HIM how to chase those details down, and sound better and better. It becomes like a treasure hunt - not the drudgery of practice.

-Lisa