Transfer of bank account of deceased mother to living father

If your father have other proofs like in his service record , ration card , aadhar card etc ...that the deceased is his wife then he can submit an application to the bank manager stating about her death and non nomination by her , alongwith her death certificate and address proof and other proofs showing her to his wife, noc from children , then the manager can accept and transfer or permit him to withdraw the money , otherwise you have to file an application in the SDM office of your area for legal heir certificate and then work accordingly .

SDM has only limited power... if ur manager is not accepting ur claim u can get succession certificate from district civil court

which will be binding on the bank