I want to know that my grandfather was a large landlord and he died in an early age having 3 sons th

I want to know that my grandfather was a large landlord and he died in an early age having 3 sons then all property caretaking and registry were done on the name of my eldest uncle at that time my father and the youngest uncle were children of nearly age of 17 ...after that the eldest uncle sold out all properties and buy new different and various properties worth in crores and all property are registered on his name and keep saying to my father  since 10 years that his share is there ..... now he is stating do whatever we can do these properties belong to him as all are registered on his name    As my father is second son of my grandfather and he is illiterate the elder brother has always taken advantage of this and humiliated him and fights horribly with him i also want to know how the loss of my fathers respect and time and the right of property of my father's share can be claimed ?? What kinds of case we can suit on him ....