What you are referring to is becoming a representative payee for your mother so that the money comes to you on her behalf.
As a representative payee, you are responsible for making sure she has adequate food, shelter, clothing, medical care, etc. Once per year,you must account for how you spent your mother's money.
In order to become a representative payee,you must call the social security office and make an appointment to meet with them. Your mother should go with you.... This is copied from the website:
Social Security's Representative Payment Program provides financial management for the Social Security and SSI payments of our beneficiaries who are incapable of managing their Social Security or SSI payments. If you are concerned that someone you know becomes incapable of managing or directing the management of his or her benefits, please call us at 1-***-***-**** (TTY 1-***-***-****) to request an appointment to discuss your concerns.
Generally, we look for family or friends to serve as representative payees.
When friends or family are not able to serve as payees, Social Security looks for qualified organizations to be representative payees.
If you are a representative payee, you can complete the Representative Payee Accounting Report online. You must be 18 or older to complete the Representative Payee Accounting Report online. If you are under 18 and a representative payee, you must complete the paper Representative Payee Report form you received in the mail and return it to the address indicated on the form.