How about a third-party alternative, and offer it to a museum or collection dedicated specifically to masonic items, such as:

http://www.phoenixmasonry.org/
http://www.gwmemorial.org/index.php

If it is documented to a masonic pipe band, and if you have a photo of your grandfather wearing it that might be able to be reproduced, it would certainly be a way to keep it together & honor your grandfather's memory.

T.