If the 4 semesters of math are calculus and we are talking about a STEM field, these classes could be really hard. With all the driving and sports, did your son get to take calculus in HS? How competitive is your D1 school, something like Bama or something like Duke?
Taking a lower level of math this semester could delay graduation, or may make other classes harder, and that class may or may not help. It depends on what is missing, the pre-calc/trig stuff or the ability to learn new material in a week or two with a punishing 30 hour a week sports commitment.
It is quite possible there is additional tutoring available for free, you can do a web search or ask your son to check or I think you could actually call the school for this question. For paid tutoring, don’t think Kumon, think upper level student, and likely there is a college resource to set this up. This would give him a one-on-one tutor who could work with him on things that he missed in HS. A more expensive option would be a professional tutor, the one advantage I see here is that you could likely interface with them directly and keep tabs on his schoolwork.
Get to those games. You have freshman playing D1, spent all those thousands of hours to take him places, and now just have no interest in something he is spending 30 hours a week on? Not to mention how easy it would be to bring by that case of Gatorade or go to lunch after the game. I think some time as a threesome,mom, dad, son could help.
And either buy books on line for him as you see fit or just don’t get involved with books and tell him to buy them himself. I buy my D her books because Amazon ships and has good prices and because I don’t mind. Mostly I get confirmation she got them, but you know it’s just not important. I just want some contact and to be there when she needs me and what she needs me for.
Mellow out and see what the next months and year bring you. Participate as you can and don’t interfere when you can’t.

