Fraud and forgery committed by my deceased sister on family asset

My sister and her newly born daughter were abandoned by her husband. Myself, the brother and my father gave her shelter and took care of her. she was a non -practicing lawyer. Subsequently, I got married. My sister was not able to tolerate my wife who was highly educated and earning very well. To have peace, I left home with my pregnant wife. Thereafter the husband file divorce petition in the family court in Feb. 2007. The same was rejected by the court in 2009. Then the husband filed petition in the Mumbai high court in 2010 and the case was continuing. In oct. 2011 my father died in a orphanage. I came to know only on his death. My sister also died in dec. 2014. After her death I learnt that she had opened my fathers locker after his death and taken out all the contents and put in her locker. against some of the jewellery she took gold loan from the same bank. Her husband closed the highcourt divorce case in feb. 2015 as she was no more. Now the husband is claiming succession to my fathers assets that were robbed off after my fathers death by my sister. 1.... Can the husband claim succession in this case. 2.. A fraud has been committed by my sister during her lifetime. The bank is refusing to co-operate with us in sharing my fathers information. But they have given out all information to my sisters husband. 3 Can I claim succession to my fathers assets. 4...How can I bring back my fathers assets.