QUESTION: Is a child required to pay for food and clothing for his parents?
ANSWER: Shulchan Aruch (YD 240:5) writes that although a child is required to feed and clothe his parents, the expense must be borne by the parents. However, if the parents cannot support themselves, the children are obligated to provide the funds (if they are capable of doing so). If they refuse, a Jewish court of law may force them to do so.
Ordinarily, a Jewish court does not coerce someone to honor a parent (e.g., to stand up for a father or mother), because beis din does not coerce observance for mitzvos whose reward is specified in the Torah (honoring parents is rewarded with long life – Devarim 5:15).
Why is kibud av v’aim different? The Aruch Hashulchan (YD 240:6) explains that beis din has the authority to coerce members of society to maintain social welfare, and children have a moral obligation to provide for parents who are destitute.