Registration with out legal hairs

Sir, 

My brother's issue,

Elder brother constable expired in 1993, survived by wife, 2 sons and 3daughters living away from the village

Second brother Farmer living in the same village survived by 2 sons and 2 daughters, living in the same village. 

In 2008 2nd brother cultivating the land of the late elder brother made a title deed for buying the elder brother share. In the same title deed, he also included some other properties. the title deed is signed by the widow mother and her elder only but her younger son and three daughters did not sign the title deed.

In 2019 the elder brother of the widow expired of health issues and in 2020 widow also expired of health issues. In 2021 the farmer called the younger son of widow and asked him to sign title deed but approached S.P of police and made a complaint against framer and his sons. The Farmer son being in police department managed S.I of police not to register F.I.R.

In span of 1 week the Farmer and his sons register land to some one else. What is course of action by Younger son?