Adopted son's rights on property

am adopted son, adopted by mothers father and mother when i was at the age of 15years and they adopted me by performing dattaka homa and registered my adoption as they were not having any successors, both of them were staying apart, my adopted mother was staying with me after my adoption till her death, my adopted father has an ancestrol property which he has named to his brothers son recently, can i have any right to fight for the property now, please guide me