How to check transmission of shares documents?

Dear All, My father died in Oct. 2014. Recently i noticed that my elder brother fraudulently transmitted some of his shares and funds (of his Private Ltd. Co.) after his death to my mother's name (and later intended to get them on his name.). However, my mother and all family members know that my father died without a Will. I read in a company document that the reason for the transmission is that my mother is the 'legal heir' of my deceased father. This is complete lie. Is there a way to check what documents were attached to prove my mother as a legal heir? Regards,