No. I don't believe in it. But neither do I see it as a crime for an adult to drink excess breast milk. What I am saying is that if you do, then there are better ways to do it then suckling your daughter's breasts (assuming story is true).
Can see from the photo that the father and daughter are really happy, hmm... Anyway, homosapiens is the species that drinks the milk produced by other species even as we matured into adulthood, imagine how it all began as caveman go about suckling the mammalry glands of the animals.