Is a brother entitled to demand from the heirs his share in a plot of land that he claims he contributed to purchasing with a sum of money more than thirty years ago, given that the father denied his entitlement during his lifetime, and that the brother resided in a property belonging to the father without paying rent throughout that period?

What a son pays to his father can fall under several categories:

1. Gift (Hibah): The son is not permitted to revoke it, according to the Prophet, peace and blessings be upon him, who said: "(It is not lawful for a man to give a gift or make a donation and then revoke it, except for a father concerning what he gives to his child)."

2. Loan (Qard): The son is permitted to demand its repayment during the father's lifetime and after his death.

3. The father taking it for his need: The money becomes the father's property, and it is not permissible for the son to demand it back, based on the Prophet's saying, peace and blessings be upon him: "(You and your wealth belong to your father)." However, this is subject to conditions: that it does not cause hardship or harm to the son, that he does not take from the son's wealth to give to another child, and that the father is in need of the money.

If what the son paid was in the form of a loan, and the father reciprocated by renting out the apartment, then the son is entitled to recover any amount exceeding the value of the rent during these years. However, if the father took the money for his need without harming the son, then the son has no right to demand its repayment.