If there are 12 DUI's there is no way he got past number three without some sort of FAA mandated treatment. It depends on how far apart they are, but the FAA generally gives you one and the second one puts you in an assessment to see if you need treatment. Now if he has kept all of this private and away from APA, AMR and the FAA, yes, he is gone, way gone. Probably will have criminal charges pressed as well.
Remember that falsifying your FAA medical app is a federal offense.