بسم الله الرحمن الرحيم
(Fatwa: 268/218/SD=3/1439)
As long as your father is alive he is sole owner of his property. According to Shariah, his children have no right in his owned property. However, after his death his leftover property shall be divided among his children according to Shariah. It is not necessary for him to make a will. As soon as one dies his property transfers to his Shariah heirs whether the deceased has made a will or not. Hence in the question mentioned above, if your father does not make a will then too his property after his death shall be divided among his Shariah heirs according to the Shariah division.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband