Actually, he did, but there are a time and a way to slip in lines that make the reader suspect that all is not quite as mentally healthy as it seems, and this fic was not it. This fic was all fluffy and lovey-dovey and then we have this line that washes all the fluffy away. (And I could tell it wasn't intentional.)

Also, I defy you to find a well-written fic, even one dealing with incest themes, where 'he nursed her breast like a starving infant is a good line,' because my imagination can't handle that.