I would suggest the following:
- His motions on the mound are rushed a bit. I would suggest a more relaxed posture and don't be in so much of hurry to deliver the pitch. Take his time to get into the setup phase of his full wind up.
- His leg lift looks good, but he rushes his lift so he gets very little benefit from it. The leg lift allows the pitcher to "load up" as it were. You son misses this opportunity.
I think if your boy were to take it down a notch on the quickness of his wind up, relax more, a lot of other things just might come into focus better. In any event, he looks very strong and deliberate. I like that in a pitcher - all business.