Vale, he looks like he's doing pretty well, you should be proud! He's going to be a strong kid.
He looks like he's not quite getting the hip drive and I think he would benefit if you took him through the hip drive drill . Have him squat with bodyweight down to the bottom and put your hand on his lower back. Push directly down and have him squat up pressing against your hand. Push hard enough that he needs to push quite hard to stand up. This is hip drive.
It's hard to tell from the angle but he might even be able to cut off the depth slightly higher. I think a little bit more forward lean could help get him a better hamstring stretch and that will clean that up.
He's lucky to have a dad that's interested in strengthening his kid.
GOMAD. As for technique, teach him to come down in a controlled, tight fashion; if he wishes to go into the bottom position faster he may do so later, after he has learned how to keep his form consistent and his muscles taut throughout the movement. Also, he shouldn't go that far below parallel, it slackens the hamstrings and reduces the amount of weight lifted.
Spar mentioned his bar position and wrists, it's hard to tell from this angle but watch the linked video and modify his bar position/form if there are any faults.