There is lots of research available online. My kid pitched LL, Babe Ruth, Travel, four years of HS, and D1 college. He sat out his freshman season in HS because of a bursitis issue deep in his shoulder that only an MRI could see. I'm pretty sure I knew exactly the period when it happened and was very wary of those coaches and my responsibilities going forward. The only coaches who liked me were his LL coach (it was me) and his HS coach, the rest tolerated me because he won games for them. Get used to that. My son trusted me, we did our homework and didn't allow him to over pitch. A couple of the best early teen pitchers I saw through these years didn't last long because of arm injuries and they were both coached by their fathers. This was due to pure ignorance and ego, it's up to you both to avoid this.
Some simple rules to follow for us were.
Rule 1). He's your kid, no one will protect him if you don't. Do your homework NOW and keep a log of his workload.
Rule 2). Teach him what you've learned, some coach's will respect "his" decisions on workload. If they don't then you MUST be heard.
Rule 3). Don't trust any coaches with his health until they prove they have his best interest ahead of their own.
Rule 4). You both must learn to say "No", because if he's any good he will be in demand.
By time he got to college he knew who he was as a pitcher and his coaches somewhat respected that.