In SoCal no one has mentioned USC or Chapman yet.
In Boston…BC, Babson, BU, NEU could work.
In NY (not sure only the city or not): NYU (especially if full pay), Fordham. In NYS, not NYC, Colgate (similar in many ways to Dartmouth though), Syracuse.
He should focus on getting healthy first and foremost, and if that means taking time off of college that is ok. If it’s in the budget, perhaps consult with a private college counselor who is experienced in transfer admissions. Good luck.