My grand mother got this ancestral property from his father and it is ancestral property. My grand mother and her sisters are the only two daughter for his father, no others.
later my grand mother has directly given this property to my brother instead of my father to avoid my share may be.
Even it was ancestral property, once inherited by female coparceners, it becomes that female's own and absolute property, that means nobody can claim any share or right in the said share of property lying in the hands of the said female coparcener. Also the nature of ancestral property extinguishes after that.
Therefore being an absolute owner of the property your grandmother has full rights to disburse the property in any manner she desires and to the person of her choice.
Nobody can question her proprietary nor can demand any rights in the property during her life time.