My mothers share in ancestral property

My mother was married to my father in 1991 my father don't have any land because my grandfather lived in pakistan and lost all of our land during partition of india pakistan. But my mother's father have almost 30 acre property in punjab. Now here I need your help. Because all this property I think will be about 120 acres. I'll let you know how. Here starts the story now. There were two brothers one had 5 chidren and one have 2. Now the one who have two children is my mother's grandfather(Dada in hindi) . This property till then has not been divided on papers but they are all holding there share and using there property. They are 5 sons and on my mother's side 2 sons. They got near about 60 acre for 5 sons and my mother's father and uncle got 60 acre for themselves. And my mother's father is now using 30 acre and and the other brother also the same. When mother was married no dowry was given. They are 6 sister all married now. And have their own home and a little property but two of them don't have any property. There is also a son of first marriage of my mother's father. And of second marriage only these 6 daughters. And right now only two or three them want their share in ancestral property and of them is widow. But my mother's father has made will also for this ancestral property I mean is this possible? Half of the property on the will is given to the boy which mean 15 acres and 1 acre to that widow daughter who live with them. And the rest of us to their self for him and for his wife which mean they both my mother's father and mother have 7-7 acre on their name on that will this I have heard. Now here are my questions: 1. Is that will valid ? 2. How can my mother get her share in the property? 3. Can my mother sell her share of property without telling them? Because right now we need money to make home and start some small business. We libe in himachal from last 30 years and really need the money right now gor further studies and for a better future.