Society bullying us, how to fight

My Grandpa is a Trustee in a society for the past 60 years. He has been control of a church property for 60 years. And he wanted his grandson to become his heir as the pastor of the church. But the council of that society voluntarily gave him retirement from his duties and appointed another pastor. The church land, buildings were all bought by my Grandfather with his money but in the name of the Society. But now they are bullying us. The question is, can he challenge the retirement order in the court? or can he write a Will stating that this property will be transferred to another trust or to his grandson and appoint him as the legal heir of the property? The council of 5 members gave him retirement without the consent of the general body. Every decision they take against any trustee is done by just giving a letter without the voting of General body, is that legal? Kindly answer these questions. Thanks.