J.M.
This may seem outlandish but if she is having a difficult time at work, she should find a friendly HR rep (outside of her branch--at corporate) that she can speak with. Let her know she can and should file a grievance if she feels she is experiencing age discrimination (she is legally protected against discrimination based on her age). The sooner she goes on record about being squeezed out, the more weight her claim will hold if things get worse for her later down the road. Tell her to ask for additional training, or even to be moved to a different position or to a different location or anything to get her out from under the poor management that is making her feel so badly.
It would be best if she could keep her job and so often people feel so demoralized that they don't take the routes that are built into most companies to allow people to continue on working when turbulent workplace situations arise. It might also make her feel better to stand up for herself.
That said, I agree...if she gets laid off or fired then she does qualify for unemployment, she can pick up some babysitting afterschool hours for older children (where there isn't so much physical running around type stuff). She can do some kind of senior companionship thing where she visits elderly people and takes them grocery shopping or brings them groceries or something (families will often pay for a few hours to have a friend come and visit and make lunch and stuff while they are at work). With her years at the bank and customer service experience she could work in a call center or as a receptionist somewhere answering phones and giving directions (which can be really fun if she likes to chat with people). Look around at local museums or places where there are alot of hospitality type positions and see if anyone is hiring. It might be a nice break to be around happy people for once, instead of grumpy bankers.
Good luck to your mom.