Rights to the name. We're primarily concerned with trademark law here. And based on trademark law, your friend has no rights to the name. Trademark law doesn't care much about who created a name ... it only cares about who's using it, and in particular, who used it first (in this case for restaurant services). Your friend would be unable to register the trademark because he's not using it in commerce and it doesn't seem like he has any intention to use it for restaurant services. Therefore, (and because copyright law doesn't protect names or short phrases), your friend doesn't have any claim to the name. It doesn't sound like there's a contract issue either because he was apparently paid to revamp a restaurant's image and arguably, changing the name and logo is part of the image. (By the way, as you can imagine, restaurants can get very litigious when it comes to naming rights.)
Rights to the logo. As for the logo, the same rules as used for the name (above) would probably apply if the logo was simply a stylized version of the name -- that is, basically some fancy font work. If the logo is more than that, perhaps a drawing or sketch, something "artistic" like this, then your friend may have a claim under copyright law. He would need to demonstrate that the work was sufficiently original and he should consider filing a copyright application. However -- don't you hate it when there's a "however" -- even without an assignment of copyright, the restaurant probably has a reasonable argument that your friend granted what's called an implied license to use the logo. Under this theory, the restaurant might have limited rights to use the logo but would not own the copyright in it. The implied license theory is also strengthened by the fact that your friend has been aware of the use for a year or so and never complained. We're not guaranteeing either that the logo is copyrightable or that the implied license theory will fly (we are lawyers, remember?) but those are the ways these disputes sometimes play out.
How your friend can handle it in the future. If your friend wants to avoid this outcome in the future, he needs to establish that in his contract -- for example, that he shall be paid a fixed amount if the name is used, etc. Or, alternatively, that if his logo is chosen, he shall receive a bonus. Practically, that's probably not an option unless your friend is in the upper echelon of restaurant consultants.