Best FD option

Amount?

15 lakhs @saucap

Considering your father is retired, put the amount in SCSS. The interest rate is locked in at enrolment for 5 years (8.2% currently) and it's backed by the Central government.

SCSS and PMVVY

Split the amount with couple of small finance banks which are backed by RBI insurance. Senior citizens will get interest rates of 8.5%- 9% and above.
https://m.economictimes.com/wealth/invest/3-ban...

1 suggestion- If booking fd, put it for highest tenure available. As we are at almost peak of high interest rate cycle. U might not get same interest rate after 1 or 2/3 years.

SCSS   or state finance  corpns like TNPF

if a tax payer and can manage wi/o interest , the interest  may be parked in a PPF 

Thanks for your suggestion @drjpatwa

Thanks for your suggestion @manehari

Thanks for your suggestion @Espionage

Thanks for your suggestion @asli_shashikant

Thanks for your suggestion @Chudiya

But can someone tell me what is scss

Many small finance banks offer FD >8%

TamilNadu mercandile Bank - one of the famous bank in tamilnadu offering 8.5% interest for 300days for senior citizen