wow.
I would say the truck needs to be moved because of it not being insured, but I think your brother needs to be punished and your parents should know. I think you should call your mom at work and tell her. Then if you can, have someone take you there so you put gas in it and drive it home. Then tell your brother he needs to tell your parents what he did (he doesn't need to know that you already told them). If he chooses not to tell them on his own then take him into the kitchen set him in a chair and in front of your mom say "do you know what I had to do today... Johnny (whatever is name is), why don't you tell her." (tell your mom not to let on that she already knew). I would make him confess.