It doesn't matter what Mr. Nabokov does with his father's manuscript. We believe in its existence; the creation is already doing its work.
The Laura manuscript is a creation designed to literally enact what Pale Fire literarily performs. It creates a vortex of literary analysis, academic speculation, controversy, theorizing and other commentary, with itself at the eye of the storm. In this way its author both distills his life's work into its purest essence and reveals an entirely new kind of literary creation.
The Laura manuscript is the purest possible fiction. It exists only in our imaginations. Perhaps the pages are blank. Perhaps they do not exist at all. Or perhaps written on the pages are the author's own description and explanation of his plan, for us all to read, analyze and discuss in perpetuity.
Whatever the case, it doesn't matter what Mr. Nabokov does with the material of his father's manuscript because it exists outside the realm of materiality, in the imagination of our culture.
Sam