Property gifted by gift deed remarried and revoked the deed

My father sold his own property to her first wife as written in registered document and after her death he gifted the property in 5 shares to three sons and one daughter. He divided in 5 parts a,b,c,d, & e. The d part is among all the three sons. The d part position was not handed to sons and kept on his possesion. After remarrying he revoke the d part which was gifted among three sons and gifted by registered gift deed to third wife & two sons without informing court or first wife children. Now the property is in possesion of third wife & two sons. since 30 years paying property tax and other utilities. The first wife sons has approached court and claim on their d part. Please let me know what is the percentage of success for first wife sons and for third wife sons.