What if what he has published is stolen? What if his speech is a manifest lie? What if he has lied about who he is on his job application and about other things.
Theft is not protected speech.
What if his speech is a manifest lie?
Then it should be disproved academically and his reputation suffers accordingly. Otherwise it's just opinion, and opinion is protected speech.
What if he has lied about who he is on his job application and about other things.
That's a question for the university to decide on.
I'll add to that: What if he plagerized art work and made money off of it?