How to correct follow through?

I have a 15-year old son, and one of the issues that prevents consistency in his shooting is that is hand finishes "pointing the the left". Some people say that your hand should finish as if it's reaching into the "cookie jar". But his hand finishes in a "cookie jar" that's way to the left of the hoop! I will attempt to attach a couple of pictures to show the "correct" finish and one that shows how his hand finishes.

Any advice on how to correct this, thank you! We've talked about it over and over. I will rebound for him, and every time he finishes "left", I will hold my hand in the air in that position to show him how his hand finished, but he continues to have that hand flop to the left.

thank you!

As I have gained coaching experience I focus less on technique and more on results.

Does he consistently shoot straight?
Does he get sufficient arc on the shot?
Is it a soft shot that has a decent chance of going in?
How's the distance control? Does he consistently miss short?
Is it an efficient shot that can be released quickly?
Does he make shots?

I'm not saying every kid should follow through just like this, but here is a better example of a good follow through (plyaer #25)
http://developyourbballiq.com/shooting-the-follow-through/

I am like Jeff - I LIKE RESULTS.

I had some kids that had the worst form in the world... slling shot, side spin etc. BUT, they were scorers so I wasn't about to mess with their shots.

So, how well does your son score % wise? From the FT line - 15 feet - and thres? IF he is a really good shooter, I;m not so sure that I would change it. JMO

My next question is this..... does your son WANT to change his form? IF he doesn't, you are wasting your time.

Right now his "muscle memory" is telling him to release the ball that way.... so, IF he wants to change this, he will have to put in a lot of time and shots to correct that part of his shot. 100s to 1,000 repetitions.

You can do this a few ways.... you can work out with him.... 10--15 feet apart and have him shoot the ball STRAIGHT out to you with the correct form........ then you can do the same thing only now with some arc.
He can stand by a wall and shoot the ball with ONE hand using the correct form. Then he can do what we calld BEEF check..... from one block - middle and then the other block.... one hand, shoot the ball with proper follow through.

This is going to take 1,000s of shots, maybe less, it will all depend on how we responds.

But, a fter all this being said..... IF he is a GOOD shooter..... I am not sure that I would mess with it... IF he is not a good shooter, then its time to change that and work on his shot. GOOD LUCK

Coach Jeff and Coach Sar,

Thanks so much for the quick and insightful responses. This helps me to simplify my approach with him. I was looking at the possibility of frustrating him with all the drastic changes I had in mind. Instead I'm going to keep it simple--If his feet are positioned well on takeoff, and his stroke is smooth and straight, we have something to work with. From there, I plan to use the practice techniques I've read from this website and the materials that I've purchased here. A lot of good stuff. Coach Tom Nordland had some very good stuff that will help his percentage go up, which it needs to. And the changes won't be nearly as drastic as I had in mind, though a lot of work is ahead of us--but that was the case anyway :)

Thank you!