Criminal Law Questions? Ask a Criminal Lawyer.
Dear Customer - You shouldn't do anything except get a lawyer for your son and not talk to the police. Getting fingerprints is a waste of time since the driver of the vehicle is deemed to be responsible for its contents whether he knew or didn't know what was there. I assume this will be in juvenile court but these drinking offenses are serious and I doubt any reasonable person would believe that your son had no idea that booze was not allowed in a car where no one was 21 years of age.
If you try to make it look like he was just an innocent bystander it will be worse so I would say nothing. If you can't afford a lawyer the court will appoint counsel but I strongly urge you to get an attorney and not try to handle this by yourself. Fortunately the penalties are usually less severe for juveniles than for adults and the fact that your son was not drinking is a good thing. All of this would go to mitigate any sentence but in the end I'm afraid he will be held responsible for the fact that the car contained alcohol and open containers since he was the driver and in control.