Delayed OPT application


Registered Users (C)
My brother completed his MS in Electrical Engineering from a reputed California university. After his completion of degree, he had to leave USA for family emergency. He never applied for OPT. He left USA in Jan, 2018. Since he has never filed for OPT, can he apply for OPT now? He still has F1 visa (until 2021). Currently he is out of USA. I couldn't find any relevant information about timeline of such submission, so thought of asking around here. Thanks!