"The staff" is most likely the group of individuals responsible for curating and maintaining the archive. A first step would be to search for any contact information associated with the archive, such as an email address or phone number listed on their website. Another option might be to attempt to visit the physical location where the archives are stored, if possible, in order to speak with someone directly who may possess information regarding "Mother" and other items within their collection. There might also be some other resources available online that you could consult in your search.