Well if he is young enough to pass off the DUI as a learning experience that would be a big help. Maybe 30 would be the deadline for that song and dance. If it happened after 30 wow, I can see it really being a problem. I carry a DUI machine in my car and if I have any doubt whether its questionable that thing comes out for a sample. We had a thread a few weeks talking about how many busted rides will affect what outcome and I think Rick explained that over here. Part 135 seems to be only hope and my guess is with a DUI even that route is rather dim in this economy. I know the outfit I flew for was paranoid about alcohol, although busted rides would not matter except for eliminating candidates. These companies tend to make sure you fly well enough using their own check pilots so they are not worried you are good enough once you get hired, they know whether or not you are. It's just getting a chance that may be the issue.

[Edit] Here's another thread. This one seems more encouraging.