If the son is receiving SSI, he has to show he remains eligible. They know he received $11,000. Unless he spent it, his assets are too high. He has to show how it was spent. Also, if he is receiving income "in kind" -- free room and board -- that may disqualify him.
If the son is receiving Social Security and one of his parents is the "representative payee," as I explained earlier, they have to show what they did with his money. If they claim he paid rent, they might be asked to show they reported the income.
Tax preparers should know enough about helping poor people, even if they can't pay fees, in order to avoid giving bad advice to the rich relatives of poor people.