What do you think is wrong here?

Need your opinions.. when my friend goes on public (such as a store, wal mart, etc), he begins to swallow excessively, his heart starts racing, and he begins to almost feel sick, he puts his shirt over his face in case he pukes, but he never does, he just swallows 20 times over and over... this has been going on for the past week and a half... as soon as he leaves the store, he feels better.. he pretty much stays at home because this is what happens when he goes out to public places.. Is this some sort of anxiety? Is this treatable? Currently, he's taking Buspar, been on it a week, and still has the bad social anxiety symptoms but feels better at home, he relaxes more..