Need help in Loan Settlement/Negotiation

My father bought a used car for 9 lac. Downpayment 3 lac and a loan from IDFC first bank of 6 lac for 4 years at 18% ROI. EMI 17600

My father died on 24th August. 15th EMI was deducted on 03 September.

Now the bank is saying to either pay the rest of the EMI every month or to settle the loan on outstanding principal amount once and for all.

Outstanding Principal is 454000.

They also said for a 10% discount kind of thing if I pay full Principal.

What will be the best option in this situation ??

How can I negotiate for more discount ?? Is there any room for negotiation on the discount part ??