When renting to family at below FMRV, you can only deduct those expenses up to the income received. Expenses that exceed the income are lost, and can not be carried over.
If rented "not for profit" then schedule E isn't used, and no expense deductions are allowed at all. However, you can still claim mortgage interest and property taxes as a SCH A itemized deduction. But as usual, your itemized SCH A deductions don't make any difference to your tax liability until they exceed your standard deduction.
