It was over 5 years ago, and DUI is a traffic offense, so if I were you I would not mention it and hope for the best. I’ve had a DUI myself in the past and I no longer mention it, never has it come up in any job I’ve held over the last half decade since my conviction.
He is totally full of shit. Not listing it would be a huge mistake.
At places where I have been part of the hiring process, having a DUI in the past would not preclude you from employment. You’d be surprised how many people have had one. Neglecting to mention the DUI when asked about criminal background made you automatically ineligible for employment.
I frequently (10-12 times a week) draft judgment and sentences for municipal courts in which I practice. We spell out “minor traffic violations” to mean those moving violations that “do not affect the liscencee’s driving status”, i.e. won’t get you suspended. In my jurisdiction, major driving offenses are DUIs, driving under suspensions, driving without insurance, reckless driving, leaving the scene of an accident and having a third moving violation within one year.
I doubt you are applying in my jurisdiction, but I would use the standard - “Could I lose my license?”, if so, it is not minor.
Also, I know entities who, if they want to get rid of an employee for some reason, will pour over the applications and resumes looking for a lie - then firing is cake, even in a situation when an employee is not “at-will”.