What can you control? Do you control that which you can control? Anything else is pointless isn't it? While you are worrying and wasting energy on the things you can't control you are losing an opportunity to control what you can control. Every situation is different and every HS program is different. Can you control that? Can you choose the coach and how he coaches? Can you control what you do?
Making adjustments and dealing with adversity is not new and I understand no one is saying that. But for every HS aged player that is tinkered with there is a college player being tinkered with. Imagine being successful your entire time in this game. Very successful. So successful that college programs are vying for your services and courting you for years. You have honed your swing and approach and had immense success in the game. You are told "We want you because of what we have seen you do and what we believe you can do." And then on the first day of fall workouts your taken to the cage and told "We need to change this. We need to tinker with that. We need to change your approach. We need to try and get you to do that." And your not facing the same level of pitching day in and day out. Your facing a legit arm every single time you step in the box.
If that player is not capable of making some adjustments and still keeping his confidence, keeping his head on right, mentally tough, capable of filtering out the "I can't controls" and focusing on the "I can controls" he is toast. And I mean totally toast.
Now I can tell you this happens over and over and over again at the college level of the game. Every single level of the college game. "Yes that worked in HS but at this level" - "We don't believe your going to have long term success with that approach and swing plane lets work on this." "You won't hit the pitching we face consistently unless we ________________ . " And the fact is this isn't just hitters. Many pitchers will be tinkered with. "Arm slots" "Deliveries" "Strides" etc etc etc.
Yes some coaches can coach the stud right out of a stud. Yes some coaches can tinker a kid right to the pine. Yes some coaches end up getting in the head of a kid so much the kid simply can't play and in some cases doesn't want to play. That's where mental toughness and the ability to make adjustments and still have success comes in. In the case of a HS player how long are you going to be with this coach? Feb to May? If you are doing your work the rest of the year and you produce he will leave you alone and let you produce. If he doesn't suck it up its only 3 and 1/2 months at the most. Be mentally tough and deal with it. Overcome it. And in some cases you might just become a better player for it.
There are things you can control - control them. There are things you cant control - control the fact you can't control them. Learn how to deal with the things you can't control so you can control what you can. There are down sides to the HS coach that says "I am not going to touch that kid. He can hit." He won't get coached and he is as good as he is going to be in some cases. And there are certainly down sides to the coach that is always trying to put his stamp on a player. The bottom line is the player has to take ownership of his situation and learn to persevere and make the adjustments he has to make along the way. And there is no substitute for simply being a mentally tough player. There is one that that is for sure. At some point and time if your son is good enough you won't be in the conversation. Your son will be capable of standing on this own and winning this battle or he won't and he will fail. IMO teach him to understand there will be things he can't control. Focus on what you can and then freaking control those things. Own those things. And never allow what you can't control stop you from controlling what you can.