PPF account can be opened only by an Indian resident. However, if an Indian resident after opening a PPF account becomes an NRI, he can still continue to contribute to the account from his / her NRO or a NRE account. On completion of period of 15 years, if he is a Non-Resident he will be unable to extend the PPF account and will need to mandatorily close the account withdraw the sum.
The person can continue to contribute to the PPF account and get the benefit of deduction under section 80C of the Act out of his Indian income. The interest on PPF account would continue to be exempt under the Act.