Really - you love the strokes? I'm surprised as the technique is poor and you are normally (like me) an advocate of correct technique above all else. I appreciate he is only six but if there was ever a case for using low compression balls then that video is an advert for it!
cheers
Looks like this may be one of those rare ones where we disagree. I am going with the Rick Macci philosophy on this one, get them into a large racquet and lay the groundwork.
Remember, this is a rally and his technique is not going to be like in a drill. How would his forehand look in a hand fed drill?....just like it does at the 10-12 second mark. All the elements are there. The key is he is moving the feet and using adjustment steps to get in the right position. I guarantee if you saw him in a controlled drill his strokes would be sweet.
Macci does rally stuff like this all the time, he would be trying to get them moving, all the while correcting the strokes. But at his age, they will break down at times in rallies like this.
I would take this student all day long....he moves, he adjusts his position. Are his strokes a little wild in a rally setting, yup. But in a controlled setting he would be amazing and gradually his rally technique would match up.