A couple of on-line reference resources that may be of help.
Image Permanence Institute is a nonprofit, university-based laboratory devoted to preservation research. (Check out the dew point and preservation calculators.)
Image Permanence Institute
https://www.imagepermanenceinstitute.org/
Conserve-O-Grams are short, focused leaflets about caring for museum objects, published in loose-leaf format. While the entire library covers much more than photographs, the section on photos (#14) is comprehensive. Say what you will about the US National Park Service, they have been in the museum business for many years and represent a considerable body of skills, knowledge and experience.
NPS Conserve-O-Gram listing
http://www.nps.gov/history/museum/publications/conserveogram/cons_toc.html
IMO, you should do nothing to them except afford proper storage. Gelatin-Silver images (be they Glass, Nitrate, Acetate, whatever) should be stored individually in acid-free, buffered envelopes. Glass can be stored indefinitely at room temperature, relative humidity circa 30-40%. Nitrate and acetate can be stored at zero-degrees (F) or less. (Apparently deterioration is negligible if it's cold enough.) Other than silver (eg, color) probably calls for acid free, but NON-buffered.
They can be contact-printed to modern films, but the process is enormously labor intensive. Next best is a high-resolution digital scan. The resulting archive is something that can be distributed among the family. They will love you for it!
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