Very sad about your friend. I find it hard to understand why a relative would commit such cultural vandalism. Jealousy? Certainly he could have afforded to preserve the prints and negatives, or offer them to a museum. What a putz!
I'm sure you are familiar with the RR photography of O Winston Link; if not you have a real treat in store. His subject was the end of the age of steam, just on the cusp of the diesel revolution. He, with the permission and assistance of the Norfolk and Western RR, shot incredible, often rather surreal, BW photos in IIRC 8 x 10 format with multiple flash. Just incredible. He had the misfortune to "hook up" with a truly evil woman who was engaged in bankrupting him and no regard for the pictures. Fortunately he was rescued, but I don't recall the circumstances.