I have to respectfully disagree with Mr Coyle. Night VFR is can be accomplished very nearly as safely as day VFR if one uses appropriate and different flight planning criteria and cues for change of plan. In that process, you have to respect the fact that homo sapiens unaided night vision is less acute and works somewhat differently than our more typical day operation. Maintaining surface reference over areas with minimal cultural lighting can be done with adequate natural light. Personally, I'm always ready to divert around such areas and plan to do so unless everything is prefect for the proposed op.
The largest source of risk in night VFR is the same as any flight operation- pilot error, and that's pretty much true single or twin, IFR or VFR, day or night. One very important difference is that down is a much more dangerous direction at night (lest the ground smite thee unto extinction, Amen), the safe response is almost always UP when issues arise. If that's not a desirable, comfortable option for whatever reason: ceilings, fuel, ice, IFR ability, then one has to be ready to abort (much harder with visual limitations) or not go at all and decline in spite of "mission pressures".
I don't know the pilot or what happened in this event. But I don't see the basic flight profile as necessarily significantly more hazardous than that of the typical helicopter flight.