Procedure of partition of hindu undivided property

Religion:Hindu. A joint family of two brothers among the five brothers were given an acre share from his dad and both the brothers decided to stay together. They started of with those two acres where the elder brother manages the paper work and financial holdings of the house the younger brother was always involved in taking care of the agricultural land and cattle. In 1985 the elder brother's wife passed away and he had 3 year old daughter. Younger brother had a son who was by then 13 year old. As days passed by the brothers worked hard and earned some good amount of property. Most of the new properties were on the elder brother name and the younger brother always trusted him as they were living together as a family. In 2016, the elder brother passed away and the family realized they didn't have any ownership on any of the properties. The elder brother daughter claims the ownership. Is there anyway to get justice for the younger brother, he is my friend. Please assist.