As others have said, it is possible to be a successful med school applicant and an athlete but you both will need to be flexible and creative to get everything done for a strong application. My experience is that different advisors (athletic vs. academic) will try to get him to focus on one thing or another, he and you will need to work the balance.
All med school applicants are expected to have doctor shadowing and meaningful (clinical) volunteering, and athletic accomplishments don’t negate the need to get those things checked off. Spend time investigating the med school application process, if that is the path he is set on, and map out how to squeeze everything in, it will not happen on its own and also doesn’t need to happen in 4 years. There are lots of med school students who take a fifth year in undergrad school or apply in a gap year (after graduation).
Something to keep in mind when trying to balance med school requirements and sports (at any level), the med school application calculates an overall GPA and a science GPA based on an AMCAS formula. The form has a place for the grades of the required classes, regardless of major, and grades are not entered by semester. There is no benefit or allowance given to students who take a hard major or a “heavy” work load in a competition semester. That means your athlete can take all “weed-out” classes like Bio, Org Chem, BioChem, Physics either in summer school (at a university, not a comm. college) or at the very least in a light, non-competition semester. There is also no benefit to cramming all of the necessary 100 level classes into the first year or taking a hard major.
The med school application process follows a yearly cycle, with initial apps going in during the summer, secondaries (MORE essays) are due in late summer - early fall and interviews run from Oct – Feb. Most schools have a pre-med society or student group that will help him learn about the process, because just like athletic recruiting, getting into med school will be much more likely if you understand the requirements and process, and develop a strategy.