Sold My Ancestral Property And Not Giving Any Right In New Properties

How can my father get his right in property? (Hindu) MY GRANDFATHER DIED WITH NO WILL LEAVING HIS 3 SONS BEHIND,MY FATHER WAS MINOR WHEN MY GRANDFATHER DIED ,THE ELDER BROTHER MY (UNCLE) SOLD ALL THE ANCESTRAL PROPERTY AND BOUGHT NEW PROPERTIES AND KEEPING ALL THE NEW PROPERTIES ON HIS NAME GIVING NO REGISTRIES TO REST 2 BROTHERS..YEARS HAVE BEEN PASSED AND MY UNCLE SAYS TO MY FATHER THAT ALL PROPERTY IS HIS AND HE WILL NOT GIVE ANY SHARE INTO IT ..SO I WANT TO KNOW HOW MY FATHER CAN TAKE LEGAL STEPS AND CAN GET HIS JUSTICE