Partial partion case of joint family

My grandfather passed away in 1989, leaving a registered will that divided his property among his three sons. Crucially, the will stated that upon the death of my unmarried uncle (Chacha1), his share would go to my brother and me. Chacha1 died about 25 years ago. My other uncle (Chacha2) sold his share of the property a long time ago and isn't involved in this situation. My father and Chacha1 lived with us as a joint family. After my father's death in 2022, my brother filed a partition suit against my mother and me. He's claiming one-third of the entire property, saying it's our father's share. He mentions in his plaint that my brother and I are the rightful heirs to Chacha1's share according to my grandfather's will, but he's deliberately left Chacha1's property out of the suit. He says there's no dispute about Chacha1's property, but his actions show otherwise because he clearly doesn't intend to divide it with me. He's trying to do a partial partition, only focusing on dividing what he calls our father's share equally between himself, me, and my mother. My father, mother, and I jointly paid property taxes and utility bills since we lived together as a joint family. My brother never contributed. We all had joint possession of the property until 2022, and we still do. I filed an application (Order 6 Rule 17) to include all the properties, including Chacha1's, in the lawsuit, but the judge hasn't ruled on it yet, probably because I'm a respondent, not the one who filed the suit. I also argued in our written responses that partial partition isn't allowed, but the judge ignored that. My brother and his wife have made false accusations of dowry against my mother and me, and I think it's a tactic to try and take control of Chacha1's property. Right now, my brother has a bigger portion of Chacha1's property than I do. The partition case is scheduled for cross-examination soon. My father also had a registered will before he died, giving all his movable and immovable property to my mother. My brother is challenging this will in the same partition suit. Here's how the property should be divided: Father's Property: Divided equally among myself, my brother, and my mother. Chacha1's Property: Divided equally between my brother and me, as per my grandfather's will. I need legal advice on the best way to get Chacha1's property included in the current lawsuit. Should I keep trying to do it in this case, or should I file a separate partition suit just for Chacha1's property? What are the implications of the false accusations my brother and his wife have made? How can I protect my rightful share of both properties?