With property damage liability on the car, the policy should pay for the damages your son caused to the light pole. PD covers the policyholder if their car damages someone else's property. Usually it is a car that is hit in an accident, but it could be a fence, a house or any other property damaged in an accident such as a pole.
For the damage to his own car though he would need to have collision coverage on the car to have its damages covered.
Collision covers damage to your car when your car hits, or is hit by, another vehicle, or other object, such as a pole. Pays to fix your vehicle less the deductible you choose.
Without having collision coverage on his vehicle your son would need to pay out of pocket for the damages to his own vehicle that it sustained when it hit the pole in this one car accident.