Uncle illegal named all property in his name.

My father in law were 3 brothers and 2 sisters. My father in law and one of their brother died in 2007. After that father of my father law died in 2010. Now we came to know that after the of their father, brother (one who is alive) of my father in law had illegally made a will in date (before the death of their father) and named all the property in his named (After the death they took the thumb print of their father on will as well). In the will, they have written that, i am the only son of my father and I have 2 sisters. There is no where written about the passed sons (My father in law and their brother) in the will. There were 4 property in named of their father (1 shop, 1 house and 2 lands). He already sold both the lands. Shop is under his possession and in home currently my mother in law and widow of other brother are staying there. There is one more land in named of mother of my father in law under his possession only and mother is staying with him in their new house. We have asked so many time to register the house in name of my mother in law and widow of other brother. He is not ready to do so. One property is in name of my father in law and he is asking to register that property in his name as well. My brother in law (Only son)is totally handicapped and on wheelchair. Can we submit an application in DC office for the same as house in under their possession? Please suggest what we can do now, we are in deep trouble.