Complicated case

My grandmother and grandfather had 4.75 acre of land. There are 5 brothers and 2 sister. First my grandfather passed away (1994) and then my grandmother (2010) without dividing the land. Before my grandmother died she asked her eldest son and 3rd no son(my father) (both had government job) to help the youngest son (unemployed). My father and uncle(eldest son) spent lakhs of rps on my youngest uncle to help him do business,but he failed every business. They also helped him in his marriage and told to keep opting for child until a boy . eventually my youngest uncle landed with 4 girl and finally a boy. After this my oldest uncle had paralysis attack and required daily attendant for his regular daily routine. In those days my eldest uncle wife was very unhappy with his husband habit of helping his youngest brother with lakhs of rps for business and taking care of his marriage and children despite of not getting any crops(wheat for eating).she fought with my uncle to not help his youngest brother and focus on his children(3 brothers and 2 girls). So she along with her children didn't pay attention on her husband health and fought with him in his paralysis days. So my grandmother with his youngest son came up with a plan to use this opportunity and exploit this situation. They took my eldest uncle in his paralysis condition to registrar office to make a will to donate his part of land(0.79 acres) to his youngest brother name and did the same. My eldest uncle was frustated with his wife and children nature and hence made a will secretly in his youngest brother name without letting his wife and children know of anything . After making a will he passed away. After 2-3 years my grandmother asked my father(3rd son with government job) to do the same as done by eldest son for betterment of youngest son future. So my innocent father (illiterate)went to register office thinking that he is doing same as done by eldest son. But in actual my youngest uncle was smart and instead of making will (as same as done by eldest brother), he took my father sign inside registrar office on registry of his part of land without my father knowledge of anything.my father blindly trusted his youngest brother thinking that every thing is done same as done to his eldest brother. After 10 years we came to know that my youngest uncle was evil and intentionally failed all business to acquire his 2 brother part of land (who was in government job). Now the situation is÷ my eldest uncle family thinks they have their share of land without having knowledge of the will, my father part of land is in name of youngest brother. Also my youngest uncle didn't divide the land equally, 1 sister has only 0.1 acre only and other sister name has been illegally removed after her suicide ( with help of other lady standing in tehsil and relinquishing her part of land). my father meet accident and only me & my brother is taking care. My youngest uncle told everyone that he will not help anyone.