Just a thought Edelweiss.
imagine if someone cut you off from internet..removed the place that even bws fills.That indeed is what the mail will represent for you Mother.
Staff often have limited training..those at the top do..often in business and money making.
Replacing the area that the mail meant means being creative...postcards...sent from wherever you or your brother are..something tangible that she can hold...pen friends...even one who dialogues about whatever interests your Mother from her past...
fan clubs...writing to the newspapers.magazine subscriptions..talking books
having a student take notes for a memoir...she needs a reason..a reason that was tapped into by the mailshots..
I'd send a card from here regularly .
Staff are fickle...whatever you see at first often is uncovered just like any group..but there is life after...lets just find what it is for your Mother.