Partition of family property at thumpamon

my father died this year on July 11th 2019 . Before his death as per my knowledge he has not prepared the will of our ancestral property. my mother died much earlier. Now my younger brother and sister are declaring by themselves that they are their property and I cannot get anything from the same and forget about it....as I have married a Hindu girl and she was not converted into Christianity....and you did not look after my father. whereas being the elder son of the family I had done all my duties my father wished except conversion my wife into Christianity. Now please advise how to get my share from this property as my financial condition is also not good to survive.....please advise