CURRYNC:
I watched your son's video with my son, who is also a catcher. He immediately had several comments about the throw down portion to second base.
First, he said that he hates those high feeds like the one in the video. As a catcher you have to choose the lesser of two evils, either you reach for the ball and keep your legs flexed or you come completely out of your crouch and lose the ability to quickly load the lower half, but you receive the pitch closer to your transfer point. My son prefers to reach for the pitch so that he can try to maintain as much flexion and load in his lower half as he can. It's a tough balancing act, and some catchers prefer to extend their lower half, I suppose it's personal preference. Either way, it's not optimal.
Second, your son reached above his head to catch the pitch, but then brought his glove down below his belt, and the ball ended up at the mid-thigh to make the transfer to his throwing hand. He then had to get the ball all the way back up to throwing position. That's a lot of wasted motion and a lot of wasted time. Without seeing more throws, it's difficult to say if that is his norm or an outlier, but I would bet that is his normal transfer position. He should get his transfer point up closer to throwing position. His current transfer point is probably set in muscle memory now, so he'll have to really work to change it.
Third, he can improve his footwork. He's gaining too much ground with his post leg, in fact it looks like it gets in front of the stride leg. As a result, the hips are late getting lined up with second, and the stride leg doesn't get a lot of extension. Part of the issue might be that the lower half is having to wait for the upper half to get into position. If he speeds up his transfer, the lower half will have to speed up also.
Last, after the first viewing, my son looked at me and said, "Dad, that's not a 1.88 pop time." He pointed out that the throw was at least 6 feet over the pitcher's head, and the ball dropped on the bag instead of going through it, much like CabbageDad already noted. My son also pointed out that the pitcher was not watching the throw and took a couple of leisurely steps to get off the mound. Son said that he wants the throw to go right where his pitcher was standing and head high. He wants to see the pitcher almost running off the mound. The pitcher should be very uncomfortable taking his eye off of the ball, because he can hear it whizzing past him.
So those are some observations from a catcher that is about the same age as your son, with some of my thoughts mixed in. Maybe another poster can expand on them or correct any recommendations that they believe to be erroneous.