I think overall the swing looks good for his age. He is a lot to work with. Here are a couple of suggestions from my point of view:
--Get a lower stance base, what I mean is get the butt out some more and back heels slightly off the ground so you are on the balls of your feet(this will allow for more hip movement).
--instead of allowing your hips to slide forward, tell him to reach his stride leg forward(you want very minimal head movt forward in the stride to prevent hip slide)
--Let the ball get back in the swing more, it looks like he extended too early, but I am not sure of the pitch location.
--try to get your hips going before the hands start, his hips and hands go together(this is a high level action, but it creates separation and more bad speed and power.
The good news is he is way ahead of the game and has a great place to start. Keep up the good work!!!!
Coach W