Inheritance of property and further transfer

MY mother in law being the only sibling inherited landed property in Kerala from her father . She has four daughters -my wife being the second. My mother in law lives with her youngest daughter and husband. We are away and came to know that she has transferred a major chunk of her property to the youngest daughter. Her husband , out on bail, on charges of homicide and wild life offences etc has plans to sell this property with or without the consent of his wife ie my youngest sister in law. My mother in law apparently transferred the property under compulsion though the deed says it is out of love.Mother in law is 67 years old and is a patient takes medicines for psychological illness for long. My question is can the registered deed could be revoked by her. How to get the property divided legally among all the four siblings. We do not want anything till my mother in laws death. But it appears that we will be left with nothing if waited for that long. She may continue to transfer more in days to come. Can that be stopped. Does the husband has any right over wife,s property.She(sister in law) has a minor son . We are Hindus based at North Kerala working in A&N ISlands for long. What is the way out