Newsflash: Landlord is selling the house, can my inlaws be sued for taking the light fixtures they bought?

My in-laws have been renting their house for 15 years. They replaced they light fixtures and ceiling fan in the kitchen/living room. Last week, their landlord told them that he is selling the house and the realtor is coming to take pictures Thursday. If they aren’t able to replace the fixtures with the old ones before they take pictures, do they have to leave them with the house? My husband’s cousin’s boyfriend told them that they could be sued if they take them when they leave if its in the pictures that the realtor takes.