Is it permissible to divide the inheritance of a deceased father in a manner that violates Islamic law? And is the sin lifted from the deceased if the children correct the unlawful division?

If a person divides his wealth during his lifetime as an outright gift (hiba najiza), there is no harm in it. However, if it is in the form of a will (wasiyya), it is not permissible due to the Hadith: "There is no will for an heir," unless the other heirs agree. If the writing is in the form of an outright gift during the donor's lifetime, then his action is valid. Whatever the donee took possession of during the donor's lifetime, his right to it is established. As for what was not taken possession of, the gift becomes void, and it becomes part of the inheritance. The estate is to be divided according to the Islamic legal division. If there was an error in the division due to ignorance, it is hoped that he will be forgiven, and correcting the error in the division for the sake of justice is better. Equalization between children in expenses should be according to need.