UW-Madison has become harder to get into over the years. My daughters did get in (although they attended elsewhere) but I was surprised that my older daughter got in. Her GPA was around 3.5 or 3.6 and declined from freshman to senior year. She did score quite high on the ACT, and I’m sure that made the difference.
If you look up the colleges he wants to go to the college will list , in order what criteria they look at first, second, third etc. when accepting a student. Some schools look at course rigor, ACT, GPA, school/community involvement in dfferent orders. Although my d got accepted into all the schools she applied to , we considered that last year when she was considering school and worked harder in the top considerations.