That's just an honorary title, and at most places can be revoked for sufficient damage to the university's reputation. This would seem to be the case, especially because at least one of the books with the fake economics expert seems to have been written while he was still an active faculty member there.
His association with Irvine has been mentioned on national news, and although folks in academia may not realize that the general public thinks "professor emeritus" means he's still associated with the university, they're going to learn really quickly. Plus the "fake expert" thing is just so embarrassingly stupid...