I have a tough time believing that he can't find "his people" at a rigorous LAC. I'm thinking along the lines of schools such as Williams, Middlebury, etc.

DD18 knows some PG kids. One went to a rigorous school (not an LAC) and he is thriving there. Finally challenged in classes and has come out of his shell socially.

Now maybe if it isn't an elite school, but more like a school DD18 attends, he could find school not so challenging. It is a good school for her major (typically listed in top ten for the major), but overall not so rigorous. She now aces courses that she didn't ace in HS. I have mixed feelings about that.