Mismatch name of deceased person

Mr. X was born in 1942 and died in 2015. His Aadhar card bears the name ABCD, his passport bears the name EFGH, and another government ID bears the name JKLM. Since he has already passed away, his name cannot be corrected on these documents. He had three sons, all of whom have different names for their father because their father's documents did not have a consistent name. If the sons' documents are cross-referenced with their father's documents to establish the relationship, the verification will fail. According to the Gazette publication department, a Gazette notification cannot be issued for a deceased person. In this case, the sons could collectively create an affidavit affirming their relationship to their father despite the discrepancies in names across official documents. Kindly check and confirm if only the affidavit is the solution and also if it is approved and accepted by all central government departments to establish the relationship, or if there are any other alternatives. Thank you.