We're supposed to be married this week, but suddenly he's MIA...?

the whole picture sounds suspicious. Marrying someone is very serious business. You have every reason to politely call the uncle and ask if your fiance is alright and where he is. If the uncle is civil and equally concerned, then you might suggest that the family call the police and report a missing person, or you might do the same. If the uncle is impolite or reacts hostilly to that suggestion, then it's probably a good umption is that the problem is not that your guy is in a hospital or joined the foreign legion. If it ain't that, then this man is not reliable enough or doesn't have enough backbone to even talk to you about the problem, much less get married. In that case, marriage would be a big, big mistake.