Regarding unequal distibution of Agriculture land by grandfatther

My grandfather has got land as part of his share from his father (i. e from my great grandfather). This is of 14 acres. My grandfather has 3 sons and two daughters. All (including grandfather and grandmother) are alive except my father which was elder son among st three sons. My grandfather has distributed (made khatedars) 10 acres between his 3 sons, in my case to my mother's name as my father is not alive and retained 4 acres to his name. Now he wants to give or gift his part of 4 acre land to my uncle and cousins and I ask grandpa to distribute it equally between 3 sons. But he does not want to do so and want to favor one of the son only. Now my uncle cousin want to sell this 4 acres and grandfather agrees with them and of that amount will be get by selling they are denying to give anything to us and one of my other uncle. Now questions are, 1)Can my grandfather do this? a.If he can then without concerning to his sons,daughters and his wife i.e. my grandma b.My father is not alive so me and my brother are eligible to raise concerns? c.What is with the part of my father's two elder sisters (married)? How can they raise concerns as they have not got any part. Though none of the sister is interested to get her part as far as equal distribution of property among my father and uncles d. And most important thing ism, How can we stop my grandfather to do so? 2)If my grandfather is not able to sell the land, 1. what can be the reasons? 2. Guide to the process by which future disputes would not arise for the same.