You have to be careful about still frame shots and where arm positions are... I agree with southpaw that he's a bit more cocked than flat arm at foot strike... Also comparing to positions of guys like Ryan is difficult as his motion is different, he's an up,down and out guy (with momentum) which creates more time for his arm to be in position. Be wary more about how his arm gets there, down up and around or straight up (like an infielder). But don't have him throw more like an infielder if he wants to pitch, that will surely mess him up. (unless he wants to be a Kieth Folk change-up guy)
I can only tell you what I have experience with, and not through tons of study of mechanics... But the bottom half is for timing and separation, it's in the top half that speed comes from (hips through wrist),,, the top half is where you speed up to create velocity and that's not during break and coming around, it's after you've cocked the arm and prepare to throw, you don't want to speed up the bottom half to compensate for the top. I truly believe having strong legs is for support and storing energy, you're not jumping from the rubber to create more speed.
The only things in his delivery that seem off to me are his stride and his trunk, the stride may be too short and not enough forward lean creating that other separation and arm lag.
Most of the time if it feels right, it is, if he feels awkward during delivery, it's probably off.