FMC & Legal Heir & Succession Certi

I need proper guidance please. After father death (Ex-servicemen) 4 years ago applied for legal heir certification local Tahasildar office. But I got a "FAMILY MEMBER CERTIFICATE" (wife&2 sons), bottom of the certificate it says used only for Bank related purposes. When asked another Tahasildar who is a relative he also confirmed this is the only certificate in Telangana through Tahasildar office. Faced a lot of problems to transfer the properties and to sell the properties around Telangana. When try to sell the house even after transfer on to Son's name Buying persons bank asking to provide legal heir to sanction loan. ( I enquired other housing finance companies and they said at some point even after few transfers at some point some bank will ask for it , even we happened to manage the legal advisor of the bank ). Another point is to transfer the company shares, or company bank account they also asking FOR "LEGAL HEIR CERTIFICATE". WE FOUND THAT AT SOME POINT WE NEED PROPER "LEGAL HEIR CERTIFICATE" . Secondly, after 4 years in 2023 wife passed away too. So Family members are only 2 sons now. Now, want to get a general Legal Heir for all the movable and immovable properties around the state. (House, lands, car, bike, Company shares) (Previously company shares were transferred through a Family member certificate) I wonder if Legal heir is Legally heir why it has to do with movable or immovable properties? I heard there is provision for legal heir from court w/o mentioning any "particular property details"? Please help me to get clarity for my future reference too. The deceased parent's hometown is Godavarikhani, Sons are living in Hyderabad. I am new to the legal profession as an advocate in Hyderabad and the client is my cousin brother.