In the American Helicopter EMS industry.....the Federal Air Regulations (FAR's) divide operations into three Parts.....Part 91 (non-commercial/private), Part 135 (Air Taxi), and Part 121 (Airlines).
Weather standards are much stricter for Part 135 Ops than under Part 91, and many EMS Operators could revert to Part 91 from Part 135 when there was not a Patient/Passenger onboard when the Operator owned the aircraft and directly employed the Pilot and Med Crew.
That facilitated returning to Base in worse weather after dropping off a patient.
It also provided the cause for a much higher accident rate than for operating under the more strict Part 135 Rules.
The similarity to that situation to this one re operating in definitely adverse weather at night under VFR is worth thinking about.
It is not the Rules that get you....but rather the decision to put yourself at risk in plainly dangerous weather particularly at night.
Surely there was a Bed and Breakfast, Hotel, or place to bed down for the night where the helicopter had landed safely with the patient.
The difference in accident rates for Day versus Night CFIT accidents is quite significant.
The US Helicopter EMS Industry proved that in spades.