بسم الله الرحمن الرحيم
It is mandatory to maintain equality and justice while gifting something among the children. It is unlawful and sin to give whole or most of the property to one child and deprive the others. But in case the father gives the whole property to one child and gives it into his complete possession and withdraws his discretion from it then this gift shall be effective and that child shall become its owner.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.