My boyfriend was using a truck to take some rubbish to the dump. While he was unloading it, the car popped out of park and rolled away causing damage to the vehicle. The gentleman who works at the dump witnessed it and wrote a report. The employer is now trying to have my boyfriend pay the entire cost to repair the vehicle. He offered to pay the deductible, but the employer is now saying that the truck is a non op and not insured. We also found out that the employer knew the truck's parking gear slips before the accident. Is my boyfriend responsible for damages?