NOT the same at all! This topic has been covered over the years. You/your son actually needs to check into the overall university and then how Honors is done. UW-Madison (ie Wisconsin) has an excellent Honors program in L&S which does not force students into the same classes at all. Nor do they segregate into separate housing. The diversity in honors students’ favored dorms is great even within the same major.
First your son needs to look at the overall caliber of the schools. The regular classes at one U may be honors caliber at another. He needs to look at courses available not only the first year or two but advanced classes related to his proposed major.
I agree a larger school is likely a good place for the numbers of students with similar interests. Remember that large U’s are like cities with many different neighborhoods. you spend your time with the group taking generally the same classes but everyone has different electives for fun or to meet requirements. Large schools more often have a more diverse course listing- obscure topics to have fun with.
The stats on how many enrolled in an Honors program don’t really matter, what matters most is the available classes. Plus- at a top tier U even the regular classes are likely to be more content filled/challenging and the overall student body at a higher level.
Years ago by now I looked at some honors programs/colleges websites. For some the structure required all honors students to take the same survey courses instead of choosing an indepth course. Plus they offered nothing after the first two years. Others offered many honors options for various courses, through senior year. Housing with the masses can work well as we are all multifaceted- not just our academics or major.
It is interesting to me to hear about U-dub (vs UW)- both are strong flagships. And the marching bands. It is was also interesting for me to see how my UW Honors experience was similar to my son’s generation- many same STEM course options with content changes of course (well actually not necessarily- son’s honors calculus sequence was theory based instead of the problem based most science/engineering students need so his textbook had a 1960’s copyright).
You want the school that isn’t heavily recruiting honors students to improve their student body. Your son wants to not be the top student but with peers. There are a lot of elite U students at their state flagships.