Yes, once you've accumulated at least 40 quarters of work in "covered employment" you're able to receive SS benefit payments upon retirement.
And yes, a notice/letter to US Treasury/bank informing them of your demand for lawful money per 12 USC 411 for all transactions will cover you. This would make all income to your bank account, including electronic direct deposits, redeemed lawful money. It's a lawful money account.
In Stephen's case it may not matter since SS income generally isn't taxed anyway. My retired parents receive SS income and they never pay income tax on it. In fact Stephen may not have to file a return at all:
https://turbotax.intuit.com/tax-tips...axes/L53Hx1v9WFor tax year 2019, you will need to file a return if you are unmarried and at least 65 years of age, and your gross income is $13,850 or more. However, if you live on Social Security benefits, you don't include this in gross income. If this is the only income you receive, then your gross income equals zero, and you don't have to file a federal income tax return.