Proceedings of a decree execution after 12 years

Hi Sir, We have a land on our grandfather's Name. He had 4(let's say A,B,C,D) Sons. After he passed away, one among those 4(Let's Say D) occupied the land. So my father(B) went to court for partitioning of the property. Court had given decree in favor of 4 (Equal partitions). But due to some health issues, my father couldn't file an execution petition in 12 years and the property is still in the hands of D. Recently we came to know, from a notice in a news paper, that D had created documents on his name and he had put the property for mortgage in a bank. So please advice what are the possibilities we have, 1. Do we still have rights on our grandfather's property? 2. How to proceed to get our share of the land? can we file an execution petition? or do we need to go to court for decree again? 3. How to stop Bank from auctioning the land? 4. Do we have any possibility to file a criminal case against D(who mortgaged it) for cheating us and Bank? Please advice.