Based on what you are saying, I am not really sure why you are asking.
DUI are charged to the driver, not the owner/registrant of a car. (unless you were drunk and gave your keys to another drunk to drive you home, in some states...)
But if you were no where near the car (in fact on a layover), how can you be DRIVING ?
Do not waste your money on a lawyer as others have suggested, and read this...
https://www.faa.gov/about/office_org...tory/item18/v/
With that said, let the family member who made the mistake hire their own lawyer, or get a Public Defender if they can't afford a lawyer.
You're in the clear otherwise.