Its going to take a lot more than sectional cuts to get into a big D1 swim program. As part of the recruiting, the coach is going to talk with your S and ask them questions like what is your intended major, etc. If the coach thinks its too much they will say so. Let your S go through the recruiting process just make sure to contact a lot of different types of programs so he can meet with the different coaches and get a sense of the time commitment, etc.
As noted above its very differernt swimming D1 Michigan v. D1 Colgate v. D1 Brown. But all three will have two a days and dry land practice on top of that.
IMHO better to get merit money so that if S decides swimming is taking too much time he won’t lose the scholarship. If he gets a swim scholarship then the coach owns him. We know big 10 swimmers who could not take summer internships because they had to stay at the school and train (or lose their space and scholarship).
PM me if you have any questions or want more specific info.