Help with renting to family members

[Mark Forest]

My father is almost 90 and is having both mental and physical health problems. We own the house next door to our personal residence, and it is currently vacant as we do some finish work to it. If we rent the house next door to my father are there any legal issues I need to address? I seem to recall there are some cautions about renting to family members. I assume we will have to charge him fair market value rent. Thank for any help you all can offer as this will solve two problems at once for our family.