Can I do anything if my father makes a will in the name of his grandson?

Myself daughter of my father. Some months back my brother beaten me and also dislocated shoulder of my son. After this incident my parents come with me to my in-laws house and forced me to not file complaint of this act, and I agreed upon this. At this time my parents agreed to give me RS 1 crore from the share of ancestral property and said I will not take property When my parents gone back to their home , my brother beats my parents. During this course of time my father was detected with cancer, so I helped him for the treatment . Now my mother is saying that we will give you RS 50 lakhs ( Previosly 1 crore). Now my father is ok and again gone back to their home. Now my mother talks in favour of my brother and brother not even interested to give RS 50 lakhs, but my father interested to give one-third share to me. 1) What can I do if my brother makes a will ( at village level with the help of village lambardar and other gawaah due to lockdown )of this property in the name of his son (by taking my father in confidence or by making wrong promises to my father). Because at this stage my father is with me and little bit depressed and my mom is with my brother. 2) What else can I do to take a sum of Rs50lakhs or one-third share from the above said property. 3) Can I challenge such will in future