You can fly in really horrible weather while VFR in a helicopter. The object is to get there safely, so if you are low and following landmarks, you keep your speed slow and be prepared for an unexpected landing to wait out the weather or abort.
The S-76B has PT-6 engines and is the only version to have that engine. There were known issues with that model, but the overall safety record is about the same as other versions of the S-76. I flew A, A++ and C++ models and they were very reliable aircraft.
If they were flying in those conditions faster that 80-90 knots, something was terribly wrong...