Is it permissible for a father to favor some of his children over others in treatment, such as punishing one of them for an action while forgiving another for the same action because he is older, and what should the wronged child do in this situation?

Islam has made it obligatory to be just among children in gifts, care, and upbringing, because it is more conducive to their dutifulness towards their parents and removes animosity between them. This is indicated by the hadith (definition) of Nu'man ibn Bashir: "Fear Allah and be just among your children." And his saying: "Would it please you that they be equally dutiful to you?" He said: "Yes." He said: "Then not so, in that case." Thus, discrimination among children is forbidden by Islamic law. It is permissible for a father to discipline his children through guidance, kind words, and non-bruising corporal punishment in rare cases for a child over ten years old.