A player doesn’t get drafted on performance. He gets drafted on metrics. Check out Heath Hembree on Baseball Cube. His college stats are brutal. But he threw 95. He’s in his 9th MLB season.
Draft year is when you’re 21. A junior in high school has four years to get his arm in shape and get his velocity back. Make it the priority. Getting back to 90 will get him recruited by a mid major.
Note: Freshman and JV count as a year of high school baseball. He could transfer to the Inter-Ac. But I don’t believe they’re big on a player entering to repeat junior year and not being able to play. They’re not PG schools. You would be using them like a PG to extend eligibility. If your son is a solid academic student he doesn’t need extra school. He needs to rehab and get back on the field in the summer and/or fall after senior year and showcase,