He has not put any stop loss …and he has used margin money so apart from booking loss
is there any other way he can avoid or reduce loss …(He can not hold for more than 3 months from now)

I mean using futures or options strategy?
If yes please explain.

If you are certain of more fall you can buy ATM puts which has roughly a delta of 0.5 so a 8300 lot size would be equal to 4150 which is approximately your holding size. However make sure to buy from next month puts as expiry is on 28th may so u can start from june month puts and rollover before respective month expiry!

Covered calls is probably the best way. But yeah, since lot size is 8300 and your friend holds 3000, it is a little tricky. But assuming u keep writing calls every month, you can recover some money every month on the holding.

But the tougher and maybe the right decision is to exit the stock and maybe buy shares in a better bank. That would probably be the right play, but tougher because of

@curiousvi first of all please explain margin money part. Which broker? Icici direct has margin equity cash segment where one can hold position for a year paying daily interest of 0.0049 percent on the purchase value.

Did ur friend use something like that or he bought any loan and invested that?

Ask him to calculate m2m loss. If he can arrange funds best is to take delivery. It is not wise to sell this season when banknifty is trading at huge discount.