My in-laws bought a home in Florida to live in during retirement. My father-in-law passed away and they never moved into the new home. My mother-in-law continues to pay the mortgage and all the expenses (utilities, water, etc). One of her sons & his wife are living in the home and paying rent (which is less than the market rate for rentals in that area). Can this home be written off Sch E as a rental property or is it written off on Sch A as a vacation home. My mother-in-law has never visited the home. If her son wasn't there, she would be renting it out for market value.