[MC5C]

I had a couple of thoughts reading this thread. First, your son is doing very well with so little time on the instrument, even as an experienced musician. Second, it's not a competition. Pressuring him will not make him love the instrument any more, and I get a strong sense of pressure or expectation from your posts. Third, no one can practice for two hours at a time and benefit from the entire two hours. It's well proven that 20 minutes is the optimum time to "practice" at a time at anything, with a break, change of focus or simply stopping for a rest, then starting again. Finally, the point of playing guitar is not to dramatically improve, as though it was a race, it's to make music - art, if you will - and enjoy, relax, meditate, contemplate. Skill and excellence comes from love of the music, and time on the instrument, measured in years, not weeks.