Regarding will

My friends' grand parent made a WILL on his father's name. His father has siblings. his grandfather had written clear statement that he does not want to give his property to other children as they did not care of him in his wife. Also they have tortured him and his wife in their life. My friends' father raised his siblings, taken care their expenses and ensured that they get good jobs. after grandfather died, my friends' father asked his sibling in case they have any problem they can raise else he will use agriculture property to grow crops, as no one had raised any objection, he started doing and continued doing this for years. After few years, the sibling came and started asking for the property, they raised objection in local tahsil court, but my friends' father won the case. Now after few years of winning the case, friends' father applied for property name transfer on his name but siblings went to the high court. what should my friends' father do? and what is the chances to get the property on his name?