We have a customer who is trying to figure out how to cash their son's stimulus check. The person is in prison and his mother has a power of attorney, however, the person in prison does not have a bank account. If the person in prison had an account with us, we could deposit it and show that he had access to the funds. With him not having an account, and it being a government payment, I am not sure how to proceed.
Thanks in advance.

If the POA gives mom the ability to conduct banking transactions then she just needs to find someone that will cash a check for a non-customer based on the POA. Alternatively, mom could endorse the check as the POA and make it payable to mom and mom could deposit it and then do what she wishes with the money - really up to you whether either is acceptable.

The Treasury Department has some specific requirements on indorsements of Treasury checks by attorneys-in-fact.

The indorsement must indicate their authority to negotiate the check, using a form similar to:

John C. Payee, by
Mary L. Smith
Attorney-in-fact

Forgery claims on Treasury checks can be filed 18 months after the fact. To protect itself, the bank cashing such a check should retain documentation of the power of attorney for at least that period.