U Wisconsin is going to be a very different experience from boarding school: it’s going to be huge, with a lot of socio-economic diversity, a capital city on his doorstep, passionate sports rivalries and supporters (and the top-notch academics will be very different than what he’s used to, unless he got into the Chadbourne residential college or to a small extent applied to an Honors program).
He’ll have a leg up bc boarding school kids know how to advocate for themselves, he’ll understand immediately the importance of office hours&writing/math/tutoring centers.
(Chadbourne may not be of interest but here it is just in case:
Chadbourne is a “college” in the British sense.)
BTW there are interesting Learning communities for his major:
St Andrews will definitely be more hands-off academically, more intense, more focused study, but socially it’s likely to be more similar to his boarding school experience: lots of upper middle/upper class students and private/boarding school kids among Americans and, to a certain extent, also for Scottish students (“public”&boarding schools).
Another difference: drinking is legal at age 18. There’s an oncampus bar, etc.