Good balance and decent load.
But very important, and similar to what Postpre said, you want to work on keeping the racket on the right side of his body during preparation when looking from the front. Instead of putting the racket 'behind his back'.
When standing in front of him, you should not see the racket ever show up on the left side (behind him) during preparation. Some call this "not breaking the plane" that would be defined perpendicular to the baseline through your body - again, meaning the racket stays on right side of body.
Another symptom of the same thing - notice how from this side view, you see the buttcap of the racket before his begins his forward swing - again, it's because the racket is behind his back instead of on the right side of his body. Once you correct this, you will not see the buttcap pointed toward the camera from this angle.
A lot of WTA forehands are hit as he is hitting with respect to the preparation, but most ATP forehands are hit as I describe.
The only other thing, definitely a second priority (and many players fight this) is that he opens up his hips a little early which leads to a little overrotation of his hips and then shoulders. It's not too bad but if you can get him to hold that back foot longer (before it points forward) you will get more from the kenetic chain and you won't overrotate the hips and shoulders as much.
He's got good feet and I like how he adjusts his contact point. To challenge his footwork (and make him a much better player) you'll want to also work on taking balls more on the rise instead of getting too grooved always setting up to take ball on way down.