It is very much possible to get an outstanding education at public universities. I went to the University of Wisconsin for my Ph.D. in math, and they have a fabulous graduate program. I know some of the professors there are also very devoted to excellent undergraduate education.
But my sense is that the usual outcome is a good education, and to get a truly top-notch education at a large public university, you have to seek it out. Some people naturally do this, but seeking out opportunities is a talent -- one I mostly lacked myself as an undergraduate. From what I can discern, it's easy to miss out.
Whereas at a private university there will be a lot of peer pressure. I went to Rice as an undergrad, and I met a lot of fellow students who were incredibly accomplished and motivated at a variety of pursuits (academic and otherwise). The peer pressure very much pushed me in the right direction. Although some people don't need this, or don't really benefit from it, I did.
My point is not to say "private universities are better than public" -- there are many excellent public universities, and plenty of mediocre private ones. If the Big 10 place is his only choice, then good luck there -- all of the Big 10 schools are good universities, and some are excellent.
But, if possible, I'd suggest that he be as deliberate as possible in his choice of university. I wouldn't worry too much about whether CC credits will be accepted or not; instead, I'd try to figure out (as much as I could) what the classes are like, and what the student experience is.