regarding partition suit of land filed in court civil

sir my grandfather bought a land in 1984 from his maternal uncle of 7 acres of gift/sale deed .My grandfather died in 1996.He had 2 children one is my uncle (expired in nov 2020)and my mother.My uncle sons filed partition suit in land in 1998.As the case on,preliminary decree given in 2005.Meanwhile in 2006,my uncle and my mother sold 4.69 acres of land to 3rd party informing civil suit pending for 188000 rs.In 2010,final decree given in court for separation of 2.34 acres to uncle sons.My uncle sons threatened 3rd party that they are the half owners.3rd party filed a criminal case against my uncle and my mother in 2016.The case is on.My uncle expired on nov 2020.filed In HC to quash FIR of lower court.Now how to cancel the sale deed of 2006 of 188000 rs.what is the way now the present value is 18 lakhs of 4 69 acres.what is the solution.cannot give present rate of 18 lakhs.give the solution.or to talk compromise with 3rd party or uncle sons.