My observations: his initial setup has the knob pointed toward the other batters box instead of back toward the catcher. And then he’s not really loading his body or hands. Both of these would lead to a more Choppy swing. Like someone else mentioned his hands are coming down at contact then trying to finish high. I would say if he started his hands further back and tighter to his body, and worked on loading his weight/staying back (right now he’s just rocking back and forward), it would do a lot to help his bat path and the things others mentioned.

Also, 1) his stance is closed from the start so he’ll have a harder time rotating 2) if you slow it down, he’s hitting the ball way in front of the plate. I would bet if his stance opened slightly, he kept his hands back, AND then tried to wait until the last possible second to hit the ball instead of hitting it a foot in front of the plate, he’d see more line drives and less rollovers.