Am I reading correctly, that he’s hoping to get into UNC-CH as an OOS at the end of January 2022 when their acceptances go out? Even with a 1490, getting in from outside NC will be a longshot, so that might make your decision easier. I do agree that cheapest is the best option if medical school is the goal, unless money is no object. Also, kids change their minds about careers all the time. Many consider the science classes at UNC-CH to be an effective tool to weed out those to whom science does not come naturally.
I don’t have a kid in med school (my D came to her senses at her UNC-CH orientation and switched from bio to business), but 4 of her close friends are in med school ( 3 of whom were undergrads at UNC-CH). In all of their cases, GPA’s MCAT’s and volunteer/work hours in a clinical setting meant 100-times more than where they went for undergrad. Of the 3 UNC-CH undergrads, none were accepted to med school on the first round. One was accepted to UNC on the second round, one is at Georgetown and one at ECU. Her other friend who was a UGA undergrad, was rejected at UNC in the first round and accepted to ECU.
I’m sure if your son ends up choosing USC’s honors college (which is very highly rated), maintains a high GPA and does well on the MCAT’s - he will have many opportunities for med school.