Kimberly,
I'm a bit confused by what you said so maybe a bit of clarification is needed. Your boyfriend is a named driver on his dad's insurance policy, right? Does this car insurance policy cover the car he was driving when stopped by the police? If yes, then there's nothing to worry about. If not, then does he have a car insurance policy for that vehicle? He doesn't need to be the policyholder (main driver), he can be a named driver but if he doesn'y have any sort of insurance for the vehicle he was driving, then the police could charge him for driving without insurance.
As far as driving without a seatbelt is concerned, he will have to pay a fine between £30-500.
