This isn't about the coach decision it's this, does cut from a HS sport inherently mean that's it...your done?
I have not read the other posts where you may have left more info, but based on your general question, the answer is no!
The caveat is related to the coach and the reasons for cutting your son. However the general rule is that even if your son never plays for this coach, it does not mean your sons baseball desires are finished. However he must continue to work hard and play elsewhere, such as travel ball teams and tournaments.
As a means of showing you this is not the end of the world, I will tell you an inspirational story I've posted before on this forum.
A player who was a starter on the JV with my son went out for the V in his Jr. year and was expecting to start or at least be a backup. Instead he was cut and it really devastated him for a short time. Yet this kid rededicated himself to get better defensively(middle infielder) and to improve his hitting. He also continued to play travel ball and tourneys. So his senior year came and he went out for the team again. My son and others were pulling for him because they knew he was a decent player and a good guy. Sure enough, he got cut again, so his HS opportunity to play was finished.
For most kids, they would have thrown in the towel, but not this kid. He worked even harder to prove to the coach and anyone else who doubted him that he was going to keep playing. Sure enough, while playing travel ball, an NAIA coach saw him play and offered him a scholarship.
This kid not only got to play, but started for the team, and was one of the best guys on the team. He is still playing and still getting scholarship money to do so.
The HS that kept cutting him was a top team in the state, so just because he couldn't make it there, he probably could have made many other HS teams, maybe even started. So by the kid believing in himself AND working his butt off every opportunity he had, he continued to be able to play.
So tell your son to keep his chin up, and work extra hard to get ready for the upcoming tryouts. If he gets cut again, tell him to pick himself up, dust himself off, and get ready to work even harder to achieve his goal.
No one coach or setback should ever mean "your done". A person is only done when they give up on themselves or the goal they have set for themselves. Tell him never to be defined by what others say he cannot do.
Good luck and keep us posted.