Does he have a killer instinct on the mound? Just curious, because I know a young man who sounds like your son. He has fairly good stuff but lacks that competitive fire, and it bites him.
One of my best friends had good velocity and great stuff. What he lacked was confidence. When the count was 2-1 he would think, "Another ball and it's 3-1. Then I'm close to walking him." This led to too many grooved pitches that left the park.
He was still lightly recruited into a good program. Post freshman year we were both in the same summer league on different teams. When he took the mound it was painful to hear a teammate yell to us, "That's pure meat on the mound. It's fatten the stats day."
To this day my friend still has Eeyore tendencies.