One thing for sure is that the bank will want to know the specific reasons for the removal request as the next-to-kin. A death certificate and a Small Estate Affidavit should do it, if he was not married and had no children.You can request copies of bank statements, mortgage documents, and other financial information from the deceased person's bank or financial institution. Letter of Instruction. Used only if there is a beneficiary named on the account. Create a professional next of kin letter. Build and share in seconds. The documents needed are a death certificate, residential proof, bank passbook, etc. Sample Letter to Bank Informing the Death of the Account Holder. The death claim letter should be written in the formal letter format.