This guy sounds a little pushy, if not creepy, showing up to your wedding. If she (or you) has advised him once (once is all it takes) something to the effect, "leave us alone", or "do not attend our wedding", "do not call", etc. and he keeps making his presence in your life anyhow, that is all you need to proceed with obtaining a restraining order and filing charges against him for stalking. If neither of you have advised him, though, in that manner and she has just "talked" to him, that would not be enough to legally keep him away. To make sure he gets out of your life and stays out, she or you must be clear in your instructions to him, "leave us alone". You only have to say it once and don't have to elaborate. If he complies for a while and then pops up again, call the police, get a restraining order, and go to court when you're supposed to. If, after a restraining order is slapped on him and he violates it once, they'll throw him in jail. That is the only legal way you can keep this from happening.
hmmbrdzz