Workn with boys t-ball????

[Dragoncoach]

This is a question about boys t-boy. My son swings great, gets in a very good position, but is too young to properly do knee cock with a negative move, what he does is transfers his wt back then strides forward as hes swinging in a very exaggerated move. Ive got him to tone it down a bit. My question is at this age should I have him just raise his heel then drop as he swings or should I keep letting him do it the way he is, or try to teach knee cock with neg move,etc?