Legal Question in Personal Injury in California

I am not sure what question you have here, so I will try and read between the lines.

Yes, your wife is responsible for the accident, as well, as a named owner. Even if your son is not liable for this accident, if the damage for the repair is over $500, it is likely that the other party filed the appropriate form with the DMV (SR-1), and if and when it is determined that your son was driving without insurance, he could be subject to hefty fines and an order to get insurance.

No, a police report is not required to determine fault. Unless your son was sitting at a stop light/sign or in traffic and was rear-ended, he is not "safe."

He is liable if the other party proves your son was at fault in court. That may be easy in many types of accidents such as rearenders. The determination by a police officer in a police report is just an opinion that may not even be admissible in court. An admission of liability in a police report only makes it easier for the other party to prove that your son is liable. If your son is at fault then your wife is liable as the vehicle 's registered owner. Your wife was required to file a form wit DMV to avoid liability. Your wife could be liable for up to $5,000 in property damage and $15k for each person injured up to $30k for each accident. Your wife should file that DMV form in case he gets into another accident. Your son can lose his licence for being uninsured and if a judgment is obtained the DMV can suspend his license and your wife's license until the judgment is paid in full. I believe that the DMV may also refuse to renew registration until the judgment is satisfied and proof of insurance is filed by an insurance company.