Err... Can he not tell them he does not accept the car being written off and he wants it repairing? The insurer is obliged to return you to the same state you were in prior to the accident. They usually declare things a write off as it's easier for them to do so than to have the repairs done and they know that most of the time they can make a pathetic payout and people will just take it as they think they can't do anything else

Had a few rows with insurance companies. Stand your ground and fight your corner and you will get what you want if you're realistic.

My mum had a 50k mile XR2i which a spotty student ran into the back of. Insurer declared it a write off.I dug my heels in and after a few weeks arguing I sourced a 2nd hand bumper which they reimbursed me for and this was then painted at a Ford body shop. There original payout offer was £300 but they ended up paying not much more to have the car sorted properly.