Car insurance

My girlfriend’s car is under my name. I pay for the car, and she is listed as an authorized driver on my insurance policy. She’s pregnant, and one day when she wasn’t feeling well, she gave her keys to a coworker to move the car within the same premises, as some parking spots get flooded when it rains heavily. Instead of just moving the car, the coworker took it to get food and ended up having an accident. He didn’t inform us about the accident, and I only found out when the insurance company contacted me about it a month later. When confronted, the coworker admitted to tapping another car from behind. Upon reviewing the dashcam footage, I saw that the coworker had rear-ended another car in stop-and-go traffic, causing damage to the back of the vehicle. Fortunately, no one was hurt. The coworker doesn’t have car insurance. What can i do or what can happen. This is in NYC