He contacted the driver's insurance to find that the driver has not reported the accident. When informed that the driver had been arrested at the scene the insurance company replied that they usually don't. Claim for new bike and damaged kit submitted.
If it's not too late, from past experience I'd strongly recommend employing the services of a dedicated cycle-accident specialist / solicitor.
I was hit some years ago through no fault of my own and due to the attitude of the woman who hit me, went through a solicitors recommended by the shop repairing the bike in order to get the cost of the work covered.
Not only did I get the repair cost sorted but upon the advice of the legal team also got a good few quid in personal injury compensation for what amounted to no more than cuts and (pretty nasty looking) bruising.
It's a bit of a scummy game but we're all (well mostly) paying for this claim culture when we buy our car insurance, so might as well take our pound of flesh when it's legitimately owing.
I hope it all pans out for the best