The rules for liability for injuries in aircraft accidents is governed by the Warsaw convention and is subject to a limitation of liability, a limitation that is worth in the ballpark of $170,000.
The exception to the limitation of liability is if the carrier is negligent or does not issue the correct paperwork for the flight.
Without trawling through the legal judgement for this specific case I would suggest the following as possible justification for a large payout.
Firstly negligence has been claimed in that Airbus helicopters knew that the fuel tanks were not crashworthy, hence the standard issue fit to production-line models and 'should' have issued a SB mandating the fitting of a new tank.
Secondly, and I hope that this isn't the case, that the passenger as a medical evacuee was deemed to not have a ticket and be subject to the limitation of liability. If this has been raised then it will have dire consequences across the medical evacuation business segment.