Is it obligatory for a married daughter to serve her father if he is financially and physically capable of marriage, lives away from his wife and other daughter, yet his wife remains under his marital care and he provides for her and her daughter?

Serving one's father is a form of filial piety, and it becomes obligatory if he needs it or commands it in what is right and lawful. However, the husband has a greater right to obedience than the father. Therefore, the wife must seek her husband's permission to serve her father. If he grants permission, then that is good; otherwise, she must obey her husband. Her unmarried sister is more obligated to serve her father.