16 year old 6'2" 190 lbs hs pitcher. short arm vs long

My son has been pitching since he was 9 years old. He has never had any arm/shoulder problems. He throws upper 70’s and maxes out at 83. He increased his velocity from freshman year to sophomore year by 10mph. I understand that he pitches with a “short-arm” delivery. Any cdomments on long arm versus short arm delivery?