Fixed Deposits

This is a case that I am still thinking over as to whether I should go ahead and pursue through legal avenues. My mother died in 2017 and prior to her passing she had made passing reference to the fact that she had created a living will stating as to how all she owned would be distributed and she had accounts created as well for her three adult children. I live overseas, my older sister lives in Mumbai and my younger brother who lives in B'lore used to care for my mother indirectly as he was the owner of the house and my mother was renting the lower unit. This went on for a period of 12 yrs after my father had passed. My mother unfortunately never confided in me about her the Will and I did not want to give her the impression that I had my eyes on the estate. After her passing my brother has not been very forthcoming and does not respond to my calls or emails. My older sister has tried to reason with him but he does not respond to her calls either. Sister does not want to proceed legally and get some answers because of the fear she might lose him forever but II am willing to do so and risk losing the relationship completely because he never treated it as though it is worth nurturing. Now I need to now how I can proceed and get some justice here. He obviously is lying to us and wants to keep the entire stash. I also want to know if there is a way to find out where my mother may have left a will. I sure do not know where to start. Hope to hear from someone out there with some plausible choices. Sincerely Vish Rao