While I haven’t seen the damaged picture, the chalky film on the surface is likely caused by mold and humidity. That’s significant damage.
The Ellis family might be able to enhance the picture using a photo editing program, but it really depends on the appearance of the photo and their skill with graphics software.
Since this is the only known picture of a particular couple, it’s worth investing in a consultation with a photographic conservator about saving the original photograph. They can find a conservator on the Web site of the American Institute for Conservation of Historic & Artistic Works .
Either way, the family also can have a copy of the photo created and enhanced. One option is to contact a photo restorer such as David Mishkin of Just Black and White for a consultation on photo-enhancement services using film photography. Mishkin gets amazing results with these non-digital methods.