As you know, Duke has offered Marshall Plumlee, the youngest of the Plumlee brothers, and if he accepts and his brothers don't leave early, that could mean that all three would be on the roster at one time. To put it another way, Mrs. Plumlee would have given birth to a quarter of the Duke roster. There's no guarantee he'll accept, of course, and he himself says here that there's something to be said for going out on one's own, and a lot of people are pursuing him.
Still, no one else can have two in-home guests at his house over the holidays to talk about their school.