Keeping open loss making branches that fewer and fewer people use just because there are a few elderly folk that don't use an ATM doesn't seem a sensible business case to me. Anyway I'm not sure this 'what about the elderly' thing makes much sense...ATM's have been around for decades so to suggest that just because you are in later years means you can't or won't use one just seems a bit odd. And most elderly folk have seen technology arrive and a lot have embraced it, at least to some degree. Again just because you are over 65 or whatever doesn't mean you can't use online banking or pick up a phone.
As for the staff I have no idea...hopefully they can find alternative roles for them but again, while difficult for them on a personal level, you can't expect a business to support loss making areas for evermore.