You cannot attribute the entire PPF maturity amount to the 2nd holder to claim it as their income; the tax authorities look at the actual source of funds. Additionally, PPF accounts must be held individually (not jointly), and since the 1st holder is an NRI, the account must be closed at the 15-year maturity mark without further extensions, with proceeds credited to an NRO account. Please consult a tax professional to resolve the irregularity of the joint account and ensure correct tax reporting.