My brother treats my car as if it were a trash can
Are you for real? What did he do to your car?
He threw his apple juice bottle in the back seat.
It's completely rude that your brother threw his trash away in your car when he could have easily disposed of it properly. He shouldn't treat your car poorly, he should treat it as if it were his own car and take care of it.
Right, he's a bum. He better not do anything to my car again.
For sure, it's your property and not his. You should try speaking up about it and his habits, and maybe set boundaries if he does it again. You have the right to defend what's yours and keep it pristine.