hitting to all fields

Mike,
I noticed that you said your son is *always* behind on the
ball. This tells me that he is not only hitting the pitch on the
outside corner to right field, but may be trying to hit pitches
that are in the middle to middle-inside of the plate to right
field also.
I would try to teach him to hit the ball where it is
pitched. Soft toss drills can be helpful. Just get to where you
can toss the ball in the air to the inside corner of the plate and
have the ball land 12-18 inches in front of the plate on the
inside corner. Just make him come out and hit the ball to left field.
Balls tossed to the center of the plate should land right about at the
front of the plate. This pitch could be hit up the middle or just about
anywhere for that matter. Since your son is learning to hit to all fields,
hitting this pitch up the middle may be best.
Pitches on the outside corner should be landing about halfway back
on the plate on the outside corner and of course he takes this one to
right field. Repetition is the key here because he will be learning
something new. Hope this helps.
tomc