Sounds good. Be careful not to overdo it with the arm. If he is like most kids his age, even though he has hit a height spurt, there is still much maturing his body will likely do in the next few years. That, along with keeping mechanics in check, should help considerably with the boost in velo he is hoping for. It just might not happen on the "early D1" timeline that kids would like it to happen. Control what you can control and best of luck.
As always, enjoy every step along the way.
Meanwhile, make sure he stays on top of grades. This is where the real college money will come from. And have him continue to research his career direction, which could ultimately be a huge factor in which schools to target.