Great coil inward as he goes forward. Very nice. Most people don't do this right.
Then you ruin it with hands behind the back elbow at toe touch. This is causing bat drag, and losing the power from the coil. Also, notice the back forearm is vertical. Should be horizontal (when you bring the elbow down the bat head should have turned around).
So, so close. This fix will make a big difference.
So, hold the coil as long as possible (you do this), and hold the back elbow up as long as possible (work on this).