It may not be too late for a round 2 payment. The new bill authorizes the IRS to get the addresses of qualified recipients from the social security administration. Round 2 payments must be distributed by January 15. If no payment comes by then, your aunt will have to file a tax return.
If her only income is non-taxable social security, she will have to make up an imaginary $1 of bank interest. A return with zero income can't be e-filed, and the IRS doesn't care about the $1 trick, it's been used for years.
