Do you mean ssi (Supplemental Security Income) or Social Security? You do not report ssi on a tax return at all. You only report Social Security or SSDI or a SSA-1099. If the SSA-1099 comes in his name he only reports it if he has other income like W2 or 1099.
You can still claim him if he is a full time student under 24. Who can you claim
https://ttlc.intuit.com/community/credits-and-deductions/help/who-can-i-claim-as-my-dependent/01/267...
They don't have to file if they only have W2 income under 13,850 (2023) but can file to get back any withholding taken out in boxes 2 or 17. But you don't get boxes 4 or 6 back. If they got a 1099Misc or 1099NEC they have to file it as self employment income no matter how small the amount.
Be sure on their return they check the box that says they can be claimed on someone else’s return.
