So, if my last name was Burger I could sue the fuck out of everyone? Because I know a girl with that last name and I'd be willing to get married to the adorable little South African racist and take her name on.
Well, it's a matter of context and the individual. For instance, in Pittsburgh Pennsylvania, some restaurant has a sub called the "Big Ben." It is obviously named after Ben Roethlisberger of the Pittsburgh Steelers since the sandwhich debuted during his rookie season and his nickname is Big Ben.
Now in his case, the restaraunt might have asked for permission first or Roethlisberger just takes it as a compliment. But I think that you would have a case in most courts if some one else was obviously profiting off of your name without your prior knowledge or consent, as I said earlier.
The "Burger" analogy is not a relevant one as the hamburger (and its shortened nickname) has been around for longer than your friend has, and your friend isn't famous to my knowledge.