He should transfer to another school. I would have lost confidence in the administration to do what is right for all it’s students. Very likely, the only reason he has not been already ousted is because of all the publicity. For just a minute or two, Purdue realizes how foolish they look. For just a minute or two. Yielding with rapid compliance to bully groups as the BLM is still the administrations first default position.
It may already be difficult for him to transfer. It is late to apply for fall term, plus he will need references etc. Any new college may be wary of him based on the publicity etc. He’s not in a good predicament, all for uttering some harmless (and sensible) remark about BLM.