On top of everything else, it's a cab, if he doesn't have all the footage from the cameras (AFAIK it's extremely rare for them not to have at least an internal, and front one*), I would hope he has an uphill struggle in the claim process.
As has been said, forward it to the insurer after taking a copy, with a cover note.
*From what I understand most cabs were early adopters of dash and cabin cams due to the disputes over claims and assaults on drivers, so anything missing should be a red flag if the cab was fitted.