What happens to a passenger (in their own car), if the person driving gets caught with drugs on them?

Nikki would likely be hauled in with this fine young man. At a minimum she would have to do some fast talking while they flog him. She needs to dump this creep and move on. Perhaps she has a little bad girl streak.

Her could be seized and sold. She could be arrested for possession. Tell her to stay the hell away from her bad boy. All he wants her for is sex and a ride.

Depends on the circumstances. If the only contraband (drugs, etc.) are found exclusively on him, then he'll be taken into custody and she'll likely be left to drive the car home. If, however, the drugs are found in the car rather than on him, then they both could potentially be taken into custody and charged with possession.

If he is arrested as the driver of her car and drugs are found in the car, within her reach, it is possible that she could be charged with possession. If drugs are found on his person (such as in his pockets) she would not be linked to the drugs.

You're not long winded. That would be me. You cousin is playing with fire. Eventually, for what ever reason, they will get stopped and boom, the drugs appear. Your cousin will also take the same ride as her boyfriend to the police station. It's not only because it's her car, it's mostly because she is with him. No matter what she says to him about not bringing his drugs along in her car means nothing to him. If she continues to see this guy she ultimately will go down with him. Do you think he cares? No, he doesn't care about her or he would give up the drugs. And from the sounds of it, that isn't going to happen any time soon. Police look at things differently than we do. They think differently. They're trained to do these things and that's why they no doubt will be stopped when they least expect it. They aren't even going to know why. Although the boyfriend will probably have a pretty good guess why. Looks like your cousin will have to learn the hard way. It seems to always have to work that way. If anything every came easy I think I would drop down dead. But that's the world we live in and everyone has to find their own way and that means your cousin. She hasn't listened to you yet. Don't expect anything else. She has to find her own way.

If he claims it then he is charged if he throws it on the floor and says he didn't know it was there it's her fault.

If they are ON him, then only he goes to jail. If they are in the car, and they can't determine who owns them, then they both go.

The registered owner of the car is charged with possession of anything in the car. Only if the item is actually in the person's hand or pocket is the non-owner of the car charged.