He is pretty good and will no doubt get better. I know local kids his age who are as good or better though. He tends to crash a little on landing because he "drops & plops". He stops at the top of most of the hits and doesn't have any momentum when he drops them. In the one section he fell as he came around the corner and saw all the pillows, I think it freaked him out a little.
If he had been down the line before I know he would do better. They don't have terrain like that at his local hill.
In the alpine part of the lesson we worked on upper/lower body separation, independent leg action, absorption, and keeping his hands out front. His Tower 3 run in the video shows a lot of upper body rotation that wasn't there most of the day. That run was at 3:50 pm after charging hard all day. He was getting pretty tired by then but was IMO still competent to ski that run. In the telemark portion of our lesson he put down some RR type tracks while doing 1,000 step and shuffle type drills. I'm pretty sure I know some instructors who can't do that.
I wish I could take all the credit for his skiing. I helped him with some things and showed him some great terrain that he probably would not have found on his own, but he had lots of good coaching before I ever saw him.