Unregistered partition deed

My father in law got share of divided ancestral property in 1982 by among brothers. It was never registered. He had 3 female children only. He is enjoying that property within family members. In 2014 my mother in law got transferred one of his property on her name. My wife don't know this. Again recently in 2023 January she misguided her daughter (my wife)and myself by not disclose her cruel intentions, again one building also registered on herself. But recently we came to know her passive executions with remain two daughters. We think we lost our rights and confidence on her. My father in law is an inefficient and older 75 years. All 1+2 are bringing grave harm to our interest. Never disclose annual incomes always telling huge debts are there moreover with remain daughters she lead extravagant life. In this junction April 2023 we lodged complaint to district collector, superintendent of police as well as to district registrar. Collector accepted as fraudulent cheating case and asked explanation from DR and sub registrar. Police people told this is civil case but I objected them. Sub registrar told u/s 58 registration act, he done nothing wrong. For his foolish statement also again complaint lodged infront of the collector. District regustrar accepted that without family members sub registrar shouldn't execute matter on favour of my mother in law. And also told her that was unregistered property shouldn't have legality to execute such heinous things. In this juncture please help and guide us. What to do. Thanks