fake will

My deceased grandfather has 7 legal heir(3 passed away ) including my grand mother. My grand mother is 83 year old heart patient and left alone by all her children except one of her daughter(aunt) she is a widow who take care of my grand mother by her daily wages and i used to help them but my aunt suffer a lot to bear my grand mothers medical expenses. My grand mother lives at chennai where the house bought by my grandfather by his own efforts. Suddenly one if my aunt daughter and my aunt were revealed a will which states they are the owner for the property after my grandfather. My aunt daughter changed EB connection and property tax on her name which was changed before my grand fathers death. Now they both torturing my aunt and grand mother to leave the house and keep in filing fake complaints in local police station and they officers are not even listening anyone except them .if she sell the house my grand mother will be homeless and her life will be questionable in this old age. They both agreed to give some 50 thousand for her but it won't be sufficient fir her because her monthly medical experience is more than 6 thousand. By these kind of activity we are suspecting this may be the fake will also my grand father was bed traits for 3 years before his dead but the registered a will on that time and witnesses also unknown persons for both my grandfather and my grandmother.  Please guide