Is the sin borne by the father alone, or by him and the children together, in the event that the father unfairly distributes the inheritance during his lifetime, to the detriment of the daughters, with the children being aware of this and accepting it?

If a father distributes his property among his children, with the stipulation that the distribution takes effect after his death, this is either a will to the heirs (which is not valid unless they approve it) or an inheritance (which is not valid except after death). However, if the children take possession of the wealth during his lifetime, there is no harm in it, provided there is justice between them. The preponderant view regarding justice is to make equal provision for males and females in the gift, based on the Prophet’s (peace be upon him) saying: "Be fair among your children in giving. If I were to prefer anyone, I would have preferred women." Preferential treatment without just cause is an unfair gift for which the father incurs sin if he is aware of it. Scholars have differed on whether the children must return what they were given preferentially without right, and the preponderant view is that the right of the donee becomes established upon the death of the parent.