See if there’s a process he can still participate in for his 1st year if he looks at the large public universities.
For a student who found a section of 40 large, and is comfortable with a class size under 15, a lecture hall with hundreds of students can be exhilarating or alienating. Has he attended a student day and sat on a few intro classes (1 math/science 1 humanities would be my recommendation)?
Students who found the lectures exhilarating typically liked to be anonymous, sit back, and listen to brilliant minds. They found having to formulate their own thoughts and/or listening to other’s, tedious or a waste of time. They liked working in groups with people they’d chosen if they wanted to, ie. wanted to organize group work on their own or not at all.
Students who found large lecture halls alienating typically liked interactive classes, small group discussion (didn’t think 30 or 40 student sections were “small group”), liked academic sociability (v. sociability around sports or partying or hall location), wanted the professor to know them by name (hated office hours with TAs or lack of personal advising till junior year for instance), liked personal contact and disliked anonymity.
As you can see from the schedule posted above, required intro chem and math classes have 16-30 students at Kalamazoo except one that seems to have more. Some of the classes are full at 30 but some only have 16 students with 30 possible spots.
Basically, if he’s in the top 1-5% at a large university he can do phenomenal research. (It’s harder if he’s not in Honors but it can be done; UC’s, in particular, do not have many honors programs, so that the top 1-5% may compete among themselves after grad students, though I suppose the Honors section would have an “in” if they’re already known by name/performance). The issue is what if he’s, say, top 25% among his peers and thus never talks to a science professor till junior year and never has a shot at any research - the most common experience for public university students.
At Kalamazoo he’s certain to be able to do research, probably could join a lab as early as freshman year, but the lab will be less impressive. The issue is, will he be able to get a summer research position at a prestigious lab (does Kalamazoo facilitate that, including for international students)?
Note that at UIUC, students don’t apply to Honors: did he receive an Honors acceptance after his admission? The latest the info is sent is April 1st. You may want to check with him because it’d make a big difference in access to professors, access to research, size of some required classes, especially freshman year.
These discussions may be of interest