Does she say that to you explicitly ? If so, ask her: If she’s just going to die, why does it matter if she’s locked out of her accounts? If she has a reason to access her accounts, she has a reason to learn how to access them.
On a mental health note, the last of Erik Erikson’s stages of development relates to old age/end of life, and the choice is between dignity or despair. If you see your mother trending toward despair, she might need help with her mental health, such as seeing a therapist.
You also might consider therapy for yourself. I get the impression you’ve got some boundary issues with your mother that you could improve. Good luck to you
Someone is going to be super triggered about a woman somewhere not liking women being portrayed as sexual objects in games and is going to post about it here