Hibba During Lifetime
If the father, while alive, properly transferred ownership to the daughters (registered transfer, possession given, clear gift), then that property became theirs.After his death i t is no longer inheritance. The son has no automatic Islamic claim over it. The mother cannot demand it back. Islamically the daughters are not sinful for keeping it.However, Islam also teaches parents to be fair among children. The Prophet ﷺ discouraged unequal gifting without valid reason. But that accountability is on the father, not the daughters.Now the daughters have a moral choice they are not obligated to give it. But if they voluntarily give some portion to their brother for family harmony, that is generosity — not obligation If the father only said verbally that he is giving it, but ownership was not legally transferred, then the property is still inheritance. In that case, it must be divided according to Islamic inheritance law and the son does have a right.