Is any of it even remotely significant compared to the £2k a year you're suggesting he throws away? No.
I mean, you're actually suggesting that he throws away say £5k over three years to save a couple of hundred quid when he actually starts using the car?
Do you even drive yourself?
A third party policy isn't going to cost £2k. Even if he wasn't covered for theft and ended up getting the £50 car stolen. He'd still save more than buying and running a reasonably priced car on a fully comprehensive insurance policy. I think that's the point Sonny is trying to make.