@Geany the couple is on Hawaii after winning a lottery right?
So the swindle is probably as follows, the swindler sells overpriced vacation packages with a free house keeping package included, and while people are away they get robed clean apart from losing their lottery money on the vacation package, but the swindler was found out, so in order to keep the old man from talking he gave away the keys of the houses he swindled, so chances are the old man has a bunch of keys in his possession.