In two banks I was in in last 20 years before and after Payment Services Directive implementation, I was a secondary user to the account. I could do almost anything on the account which saved my mother lots of stress. It's enough for her to check balance and outgoing transactions and rest lies in my hands. Wouldn't that help you as well?
In Poland we have a rather well-functioning digital services platform. Tho, two weeks ago news outlets raised a small tantrum that our digital identity wallet application may be non-compliant with the upcoming EU standards. But as for now, once you log into the application (there are few ways - ID card with chip, 3rd party login by bank and so on), the session is kept for a year.
After that's done you can log on desktops by QR code or pass data from app to app.
mObywatel app tries to include all the essentials: from digital ID copy (identity confirm, validation for you and someone else) your DNI-equivalent protection (won't allow to process your personal information in some cases). There's healthcare services handling (prescriptions, but we also have a dedicated app), inbox/outbox for official matters, payments and taxes, section for car and vehicles (penalty points, accident reporting), environment (reporting accidents, air quality, flood alerts) and travel (rail tickets wallet, tips and warning for traveling destinations - atm it shows that Spain is on 4th level terrorist threat). Tbh, it's way better than used to be few years ago with complex login flow that could break midway.
It's all convenient stuff but older generations are already digitally marginalized and we may indeed head into the future where we won't be able to do anything without a smartphone, in both real and digital life.