His hip rotation is late. Release of the barrel is sluggish. Little to no separation is created.
He IS turning the barrel in his hands, however.
Glad to see it.
The lead elbow juts to keep the hands in the zone as he resists shoulder rotation.
He will struggle with timing.....big time.
You can not generate enough momentum to generate the necessary swing quickness with the hips still closed at 'go'. They have too far to go, with too heavy a load to pull and they move too slowly. If the hips are still closed the only momentum you can create is linear...and it can't be stored. You are subject to the stopping/starting/slowing of that linear momentum as you deal with the pitchers arsenal and it simply can't work. If the hips have to turn 90 degrees at 'go', you're in trouble. They can't move that quick. They're powerful....just not quick enough.
Proper use of the hips is not defined by "how much distance they have to turn at "go", over which they can create force", but instead, is defined by "the amount of stretch they create against the upper body which can be stored and released at the right moment", the "stretch and fire" release mechanics.
This 'stretch and fire' to release the barrel, is the only way a hitter can create adequate quickness to deal with high level pitching.
The hips must have a running start as the upper body loads against them.
This hitter's hips are closed at "go".
Take a look at this guy's hips. I missed the "yes" by one frame. Should be one frame earlier. However, look at his hips at "go" compared to your son. Bond's hip line points to between the 1st base coach and 1st base dugout at "go".
The kid's hips are still in line pitcher to catcher.