It all depends on how long ago the DUI was.. the rest of his criminal history.. and what plant he is trying to hire on with. Since you didn't give many more details than that I will pretty much give you a short version. It's definitely possible but he will have a mountain to climb to get on if it was within the past 5 years... Substance abuse eval(out of pocket expense) , 5 year work history for background check.. psych interview.. if granted access he will be thrown in the follow up pool (more random testing).