Grandmother not dividing grandfather's property equally what to do

My grandfather has given all the property to my grandma before his death. My father is the elder son. I have one uncle also. My father has always supported them financially as well as mentally. He has spent 7 lakhs on the treatment of my grandfather before his death. My grandma is biased. She is not distributing the property and is willing to give entire property to my uncle. My father is already 42. He is a diabetic and heart patient. He needs some money for financial stability. How can we claim our right. (hindu)