Is it permissible for a father to take a portion of the rent from an apartment he bought for his son in installments and for which he paid a portion of the price, and would the son's refusal of this be considered an act of disobedience?

If a father singles out one of his children for a gift without a legitimate Shariah justification and to the exclusion of his other siblings, then this is not permissible for him, due to the saying of the Prophet, peace be upon him: "Fear Allah and be just among your children."

If the donee takes possession of the gift legitimately, then he owns it and can dispose of it by selling, renting, and so forth. The giver has the right to retract his gift as long as it has not left the child's possession through sale, waqf (endowment), or similar means.

It is permissible for a father to take from his child's wealth what suffices his need without his child's permission, based on the hadith: "You and your wealth belong to your father," provided that he does not unduly harm the child. A child's refusal to give his father in this situation is considered disobedience (uquq).

If a father shows kindness to his son by buying an apartment, the reward for kindness is kindness, and the son should not prevent his father from a portion of its rental income.