How can I get the "patient pay" portion lowered that my father has to pay Medicaid?

My father has to pay a portion of the amount that Medicaid pays to the home health care company. It is called "patient pay" and it is like a co-pay, and is based on his income. I am trying to find out if the monthly rent my father pays us would be deductible so that my father's amount of patient pay would be lowered? My father is 104 and lives with my husband and me. We don't currently charge my father rent, but would if it would lower his payment amount. My father has a very low income; just a small social security check and small Veterans Administration check, and no assets at all. He receives 30 hours a week of care through Medicaid and 10 hours a week through the VA. I already know about medical expense deductions, but am wondering if RENT counts as a deduction for the patient pay?