Do cops need to be involved in vehicle accident at school?

my boyfriend and his friend were messing around at school, and my boyfriend got hurt. he was sitting on the tailgate of his truck, and his friend was going to pretend to hit him, then slowly inched up to him, and didnt realize how close he was and crush my boyfriends knee with the bumper of his truck. we dont know how bad the damage is yet, the just took my boyfriend to the hospital, but our principle came out saying that the cops will need to come to the school and do a vehicle inspection and that we will have to deal with there reports and insurance. my boyfriend doesnt want to press charges or have his friend in any trouble, so what happens now? my boyrfriend is 18 if that makes any difference, it wasnt on school property but it was at lunch time, right across from the school.