Hello sir,
My father has a shop of ladies suits(wholesale)in chandni chowk... There is no profit at all.He wants to open something else as he is fed up with his (no profit)business.. He is 52 now.. please I would request you to suggest me any new business for him.

Online selling of cotton and silk and linen.

Has he considered other location, what is the business issues why there is no profit.

Since its wholesale
He might want to look into other prospects in same business rather than starting another business from scratch and no knowledge.
Your might want to look into exports in bulk quantity internationally.
Might want to start bit of retail too.
Might want to list products on sites like EBAY.
Might want to open up own small website and advertise what he is selling.
Lots he can do