IS A 'THUMB IMPRESSION WILL' CHANGING PROPERTY HEIRS ACCEPTABLE?

IS A 'THUMB IMPRESSION WILL' CHANGING PROPERTY HEIRS ACCEPTABLE?
We are two brothers and one sister. Our late parents had left a will in favour of all the three of us for equal shares in the property at Mumbai. We two brothers are living with our family out of town, but our married sister, along with her family was living with the aged parents and was taking care of them. After the death of our mother, our sister got a new will prepared in her favour as the only legal heir from our father, who was not in stable mind and could not sign and, therefore, she got his thumb impression on the new will and got it attested from a medical practitioner, who claimed that my father was in an unstable mind and could not sign and hence the thumb impression. She got this will notarized. What is the status of us two brothers, who trusted our sister and allowed her to look after our aged and unwell parents?
–Kanal Bansal
It is a case of two wills by your parents, one in favour of two brothers and the sister and another by your late father in the exclusive name of your sister. The question which is the valid will of your parents will be determined by the court in the facts and the circumstances and the evidence led before the court. Since the will produced by your sister is notarized, evidence of the notary whether your father had appeared before him and put the thumb impression on this will and the Register maintained by the notary to be produced in the court and also the testimony of the attesting medical practitioner that your father was not in a stable mind, which could be construed that he was not in a proper frame of mind to understand the contents of the will, will be material evidence to decide the issue.