My grandfather had four brothers. All the family property is now registered in my eldest grandfather’s name. How can this property be legally distributed among my uncles and father?

If your grandfather’s brothers have no legal claim on the property, it is likely your eldest grandfather inherited it. To distribute the property, the legal heirs of your grandfather and his brothers, including your uncles and father, would need to file a partition suit in court, establishing their legal rights and seeking a fair division.