Is deceased brothers kids consent required to sell fathers property

My Grandfather(A) has a property( A piece of land which I believe that it's a self acquired property). He(A) died without writing any will and thus failing to bequeath the property to his children(B,C,D&E). He has two daughters(B,C) and two sons(D,E). One of his son(D) died. Another son(E) has kidney problem and hence need money for his medical expenses and he came to know about his father's property accidentally while cleaning his cupboard. While the two sisters(B,C) are willing to help their brother(E) inherit their father's property so that he(E) could sell it and acquire money for his medical expenses, he(E) has a doubt whether the son(F) of his deceased brother(D) has any legal right to the property. Is it enough if he(E) can show the death certificate of his deceased brother (D) and the willingness of his sisters (B,C) to give up the claim for that land, to acquire his father's property? Or should he(E) also required to get the permission of his deceased brother's son(F)?