Property division issue

My grandfather owns a house and several acres of land. Now a point has come where he has decided to split the land. My mother has 2 sisters and 2 brothers. So, my grandfather has 5 children. The division which he had proposed is unfair. He is going to give the house to two sons. And out of several acres of land, he has written that he will be giving just one 30x40 ft site to each daughter. The rest will be given to two sons. So basically the son's are getting 95% of the property share. 1. Grandmother says, daughters have no right to property, they are asking to sign papers of property division. I know this is not true, I want to know which law says children irrespective of men or woman have equal right? 2. Can I ask my mom to take a lawyer to the signing and ask they lawyer to explain the law and deny signing? 3. What action can I take legally for 3 daughters of my grandfather to get their equal share? 4. Is it a good idea to get stay order for the land and the house to prevent them from selling it? 5. My grandmother says if the daughters don't agree they will get it signed from her sons and proceed. Is that even possible for a property division?