The Russians will have to get pretty desperate to take rupees.
As of yesterday, the ruble is weaker than the Indian Rupee. It was within 5% before. So not sure what you mean.
In addition India require a lot of spares for the military. And cheaper Oil. Russia will likely not pay a financial price for this war. The will earn back through higher Oil prices. Plus all their old equipment is used up. They can buy new.