Is it permissible for one of the sons to dispose of a portion of his elderly father's land and utilize it without consulting the rest of his siblings, given that the values of the land portions vary?

A father who is of sound mind can dispose of his wealth as he wishes. He may appoint any of his children or others to manage his money as he deems fit for his own interest. The rest of the children have no right to object unless the father grants one of his children privileges that constitute a gift, as it is obligatory to treat all children equally in giving, based on the Prophet's (peace be upon him) saying: "Do you have any children other than this one?" He said: "Yes." The Prophet said: "Have you given all of them a gift like this?" He said: "No." The Prophet said: "Do not ask me to be a witness, for I do not witness injustice."

However, if the father is not of sound mind (senile), his guardian becomes the Shariah judge. None of his children are permitted to dispose of his wealth without the judge's authorization.