Need advise on a property matter. Please help us proceed ?

Hi, My father's father had three brother. One of them did not have any child so he adopted my father and my father took care of him through out of his life. He made a registered will in favor of my dad and as per that will, an agriculture land which was at his name, transferred to my father's name. He got die in 2006 and mutation of that property was done in 2007. However, now after 9 years one of real brother of my father filled a case at tehsil that that property should be distribute among them as well. Tehsildar has rejected their Application on 24th April 2017 and made decision in our favor. Now they appealed at SDM office inder section 210. Please suggest, what would be the decision of SDM court in this situation. Regards, Tarun Kumar