Is the son sinful if he gives his siblings from crops given to him by his parents, who ordered him not to give them away, and is he sinful if he possesses the majority of the properties written to him without dividing them among his siblings, and is he entitled to claim his share of the remaining properties?

Parents are not permitted to favor some of their children over others in giving gifts, whether male or female, unless there is a legitimate شرعي justification, because that is a forbidden injustice. Favoring males over females is an act of the Jahiliyyah (pre-Islamic era of ignorance). The father must retract what he has exclusively given to one of his children and distribute it equally. As for the father writing over most of his possessions to his son without his daughters, this is not permissible and is considered void, as it involves disinheriting some heirs and is considered a bequest to an heir, which is Islamically forbidden. The son must distribute what his father left among all heirs according to Islamic law, unless the heirs willingly consent and are adults.