Property dispute after 48 year's

Kempnanjegowda( received his part through inheritance) and sakamma (wife of kempnanjegowda) being the owner of land had 5 children (A,B,C,D,E). A sold land belonging to ABCD&E without partition. One person had brought this land in 1969 with just a registered sale deed . Year's later in 2018 C,D&E gives right to A&B to sell their share of land. A&B sells some part of land to government and receives compensation as well . 48 year's later grandson of the person who purchased property arrives to tell that this property belongs to him , with only a registered sale deed in writing and initiates a suit in 2018. Now A,B,C,D&E sell their share of land to person named harsha after being owner and in possession for 55year's in 2023 while a case was ongoing since 2018 for title. With proper RTC, EC , MR and revenue record. Harsha sells the property to Gowtham in 2024 while a suit was ongoing without gowthams notice . Now I ( Gowtham ) want a solution. What can be done here ? Grandson of the purchaser lost case in tahsildar, ac , DC court as well . Now it's in civil court in the stage “ORDER”