Hello,
If the Person is sick or incapable of walking to the banking hall,
They can sign you check from their checkbook to withdraw money from their account.
They can also give you the Card details so that you can withdraw money from the ATM.
If there is no check book or ATM card, the person can get the contact of her bank and call them to request one.
The person can also call the bank and inform them of her condition, the person will then ask the bank for authorization forms which will legally allow another person to cash out money from her account.