From a delivery stand point, as Steven said, he could shave some time to the plate by modifying his leg kick. Also, I’ve found that speeding up the kick and stride can also increase the arm speed. Which most people believe to be a desirable effect.
How does he locate? Now, I’m not saying he’s slow to the plate, but often if the bottom half is slower in tempo from the upper half, the pitcher can tend to miss low and away when he does miss, which isn’t necessarily a bad thing unless you have difficulty spotting down and in. Also, as Steven commented, maximizing explosiveness of the stride and in a linear direction toward home can add velocity up the chain later on and makes that down and in pitch easier to locate.
If I were to continue to pick at nits, I would like to see the glove a bit higher through trunk rotation and follow through, it does seem to droop a bit.
All in all, you have a well put together delivery with good intent.
