Can an insurance company cancel insurance?

My nephew was parked outside his house which is on a farm. He was in his car with the engine running waiting for it to defrost before leaving for work. He was using his mobile to set his music playlist up for the drive. He has a black box and it detected he was using his phone with the engine on and now the insurance company are going to cancel his insurance saying he was using a mobile whilst incharge of a vehicle even though it was stationary Infront of his house. May be worth noting that his house is at least 1 mile away from a public road. This is out in the country side. His driving score has been recorded since he has had the car and it's always been above 90 out of 100.

The insurance company know the vehicle was parked Infront of his home and was stationary for at least 20 minutes before he set off and that his mobile wasnt at all during the drive.