Can you re-enlist after getting an OTH in the marines?

My fiance went awol from the marines for two years but was recently caught and brought to the Camp Lejuene Brig. He was told he's going to get a oth discharge. He told me he's thinking of reenlisting to finish out the time he originally signed up for. Is this even possible? I've read that an oth barrs you from serving in any branch of the military. Can this be just an idea of his or is it possible? He has to serve 30 days and then stay in an unit for 2 months before he's discharged, Is there a way he can re-enlist during this time?