I do work for the Library of Congress and no, it is not part of the mission of the Library to maintain a physical copy of every book ever written, though it does have extensive collections. Regardless, having redundancy in efforts will only make the efforts more effective.

Edit: To expound on my last point, It not just redundancy in the collections, but redundancy in the effort which is important. If the LoC stores two copies of the same book in two geographically dispersed locations but makes the same brain-dead mistake in preservation process at both, then it doesn't matter that there were two copies. Entirely separate organizations using entirely separate methodologies are much safer than one organization. The general process for storing these books seems to be very different than that of the Library so it is good that he is duplicating the effort.