It depends. If you are charging rent and reporting it to Social Security in order to increase SSI benefits, then you need tp report that rent and pay taxes on the income from it.
If you are not reporting the rent to social security than you do not have to claim it on your return.
You need to determine if the rent you are charging is a "fair rental value" for the percentage of the house that he is renting. If you are charging a fair rental value than you can claim rental expenses on Schedule E for that percentage of the house. Expenses should offset much of the rental income.
If the dependent is taking care of at least half of his living expenses, the parents can still claim the EITC.
