He will need to file an income tax form in April 2021 — and claim a “credit” for the stimulus check he did not receive. But he needs income to actually use that credit — and it is unclear if the IRS will only give a credit against taxes paid. I think he should go online — though the timing ended yesterday t0 the IRS website to file as a “non-filer”. Click this link to get to the right page and HURRY. Sorry I didn’t get to this question sooner!