My fiancé wants to join the Marines but ..

Al

So my fiancé wants to join the marines and I'm all for supporting him in wanting to do this. But he's not sure he can because he has a misdemeanor for possession of marijuana from when he was 18 he's almost 22 now, clean. He dosent even smoke cigarettes anymore, could he be eligible for a waver to join? He's never been in any other trouble. He set up an appointment with a recruiter. I'm just wondering for before hand.