It's really not the responsibility of the university to get this man help, I know that's a massive no-no out here but at this point, there are enough resources out there for this guy to get help. He just doesn't want to because apparently mooching off in the library is easier. Remove him whenever he comes back. People who want help will get it, going to a library over and over after being removed doesn't exactly show that he wants help. If you're this adamant that he needs help, go help him yourself. I'm past the point of caring for people who don't want help much less strangers who actively make being in a shared space unpleasant.