I am not a parent but being a D1 athlete I can give you my personal opinion. If your son truly truly loves the sport and wants to play D1 tennis, let him devote as much time to the sport as possible while still maintaining above a 3.0 GPA. If he is in between or favoring education, do not let him play D1. Division 1 tennis will become his life (a lot of travel and missed classes) and he will burn out if his passion isn't there. There is no point in playing D1 if you don't want to be involved with the sport in some manner afterwards. I know many kids that are good players but not D1 level. They do not have a burning passion to improve and sit at the bottom of the ladder. They do not receive any scholarship, yet devote so much time to the sport. A top D3 tennis program is a great option if he is in between and wants to focus on his studies for now. He can always transfer to a D1 school if he performs extremely well at the D3 level and decides that tennis is truly his passion in life. Basically, D1 tennis is a way of life just as academics is a way of life.
It is not the mountain we conquer but ourselves.