MISSOURI MIP involved in accident?

My nephew who is already on probation for MIP Minor in possesion was recently driving the car that was totaled, nobody was hurt, but this is my question......four people in the car, only one who had to do a breathalyzer was the driver who was the only one of the four under age in the vehicle, although the others were reported to be intoxicated as well, nine days after the accident the driver is given the ticket for MIP, why were the other three in the car not ticketed for contributing to delinquency of a minor, as they all are over the age of 21???