Boy, I wonder if the beaning and wild approach is going to help your son, from the impression I have of "jumping out of the box."
Has anyone worked with him with tennis balls and learning to turn away, starting with the head, to avoid being hit?
For many 10 year olds in little league, 12 year old velocity challenges them. In our area we had one veteran and successful coach who would not let a 9-10 swing the bat. They only bunted to get used to the velocity and overcome the fear.
It can be scary. Sometimes it is okay to appreciate that. The more they feel confident about being able to stand in the box, turn away correctly for pitches inside or breaking balls at them, they sometimes can get that bit of confidence they need.
Since our son at 9 years old was the smallest in his little league major division and was hitting off guys over 6' tall (taller on the mound) I have pretty strong feelings that coaching them with tennis balls and them learning to protect themselves by properly moving the body on balls coming their direction is a better approach than beaning or feeding them more wild pitching when they have not been taught how to respond with their head/upper body and the rest of the body.
Just the views of one very old guy, though.