He will need to amend his return once he receives his refund. Amend
returns take up to 16 weeks to process and must be mailed. You will need
to file your return by mail. You also need to go ahead and file an
extension if you have any taxes due. You will also need to pay those
fees by April 18, 2017.
https://turbotax.intuit.com/irs-tax-extensions/
WAIT until you receive your refund and then
Amend.
Follow these steps
to amend: https://ttlc.intuit.com/replies/3288565
