The bouncer reported that he saw the driver brandish a firearm, not that there was a firearm in the car not registered to the driver. Who has legal title to what is completely irrelevant. People are killed with guns that don't belong to them all the time.
The crime is displaying a gun in a menacing fashion. If the driver can be identified as the person who did that, or supposedly did that, the driver will be charged.
Who gets charged will be up to the District Attorney and they will review the evidence to determine who and what charges to file. Depending on what else the police have reported and the background and criminal history of the people in the Range Rover (assuming the car got stopped by the police) just the driver could be charged, just a passenger, nobody if they can't figure out who did what, or everybody if for example the authorities believe it is gang related.