What is the criterion of need and benefit that permits differentiation in gifts among children, and does what is presented in the described case, concerning the preference given to the ill daughter, the youngest son, and the eldest son, fall under these legitimate and necessary reasons?

Justice must be observed among children in giving gifts, without favoritism, as narrated by Nu'man ibn Bashir from his father that the Prophet, peace and blessings be upon him, said: "Fear Allah and be just among your children." Preferential treatment is permissible if there is a need, such as illness, a large family, or engagement in seeking knowledge, or withholding a gift due to immorality or innovation. There is no harm in what was given to his sick daughter, nor in what was given to the males as assistance for expenses or rent-free housing. However, giving them money to own apartments without justification, and transferring ownership to them, is not permissible except with justice among the children.