You do not want to break the collection up in any way. The collection as a whole is what would make it interesting and worthy of inspection by those "in the know", not any one photo. Keeping everything as is is essential to preserving any historical and/or monetary value that the material MIGHT have.
Having the negs is very important and increases value quite a lot, IF anyone is actually interested. If the pix have any writing or documentation, you stand an even better chance of interesting somebody.
It is not going to be a gold mine by any means, but the pix should at least be offered up to be examined by experts. As long as he can prove the provenance, contact Curatorial Assistance in Pasadena, CA. Graham Howe is the owner, and he may be interested. Great guy who provides a great service. If he is not interested, he can at least provide some guidance and/or point you in a good direction.
Curatorial Assistance • 113 East Union Street • Pasadena California 91103 USA • tel 626 577 9696 • fax 626 449 9603