It's thoughtful that the old man and the narrator work out a system to correspond with R’s wife, which again shows how well they’ve thought out their plan. R is a mysterious person, and his connection to his wife is not all that developed, but she is pregnant, so it’s important that R stay in contact with her. The wife’s reaction to R’s confinement shows that she is brave and that she, too, may even have seen something like this coming, since people are vanishing more and more on the island.