Acquisition of Property

Sir, My grand father is had 2 sons and they were lived together for 15 years in one house that is illegally occupied government land after the death of the father . The Elder son (1st son) was married and left the house and lived with his family another place by constructed his own house. The Second son (My father) was also married and lived with his family in the same house till to today ( nearly about 45 years). By last 10 years ago The Government of the State has issued and distributed "Patta's" ( Certificates converted Illegal land to Legal) that was issued on my mothers name. From that date to till today we paid the taxes and revenues to the Government regularly. and we also made katta in city municipality also. But now from last 3 months my Brother (Elder father son) was asking the share the same property. One thing I want to tell you that from last two years our two fathers also died. Please advice me what to do ? and he is eligible for the share of the property. Regards SURESH