Is it permissible to isolate an eighty-year-old frail father who does not respect the family's privacy on a private upper floor, providing him with food and drink, and would that be considered disobedience?

A wife has the right to a separate dwelling, and she is not obliged to accept the presence of her husband's father living with them in the house. Moving the father to an upper floor is not considered disobedience unless it results in harm. Filial piety is an obligation upon all children, and your service to your father carries a great reward, especially in his old age, in fulfillment of the Almighty's saying: "And your Lord has decreed that you shall not worship except Him, and to parents, good treatment. Whether one or both of them reach old age [while] with you, say not to them [uff] and do not repel them but speak to them a noble word." And whoever does not enter Paradise after having reached his parents in old age has lost out.