your father should submit to the bank "Form 15H" every year,( before the interest is due/paid to him, )so that no TDS shall be deducted by bank, from the interest due/paid to him.
Note that he should submit "form 15H , on year to year basis to the Bank , preferably in April every year to avoid deduction of any TDS on interest by the bank.
However if your father has failed to submit the Form 15H in time , the bank shall deduct the applicable TDS and the bank shall give you a TDS certificate at end of year showing the total TDS deducted on your a/c. Then, on the basis of this TDS certificate issued by the bank, your father will have to claim back the TDS from Income tax authorities by enclosing the TDS certicate along with the Income tax Return filed by him.
So better to submit Form 15H every year in April or so , to the bank and then no TDS deduction will happen.