My kids were able to work their way into engineering majors at Ohio State by scheduling the classes they needed (fresh/soph level) to declare their majors as DE students (last priority for scheduling, outside of CoE). At Ohio State declaring your major after completing FYE confers priority scheduling for the major classes (junior/senior level) needed to graduate. There are students having less than the minimum guaranteed admission gpa that are able to continue to make progress toward their degree (they need to be flexible on classes they are willing to take) that just re-apply and others that will choose closely related engineering majors. Mine have had great experiences and felt supported, never like anyone in engineering was trying to weed them out.
If your son is on the fence between business and engineering I’d suggest applying to Fisher at Ohio State because he has the stats to be a direct admit to their program if accepted to the university. It’s very tough to work your way into Fisher from within the university (always competitive, no clear gpa minimum pathways, fewer seats open up) and it would be an even steeper hill to climb if his gpa suffers in freshman engineering classes if he discovers it’s not for him.
Ohio State also has a joint IBE program for a limited number of incoming honors students https://fisher.osu.edu/undergraduate/academics/honors/integrated-business-and-engineering-ibe-honors which may be a good way for him to explore his strengths and interests.