Before I begin. My sincerest condolences to anyone reading this who has a personal connection to those involved. I am deeply sorry for your loss. This is an awful tragedy! I have been far too close to this type of incident myself.
The rotary skills gap between PPL and ATPL is massive
I'm not sure I completely agree.
On the basis of my reasonable experience, it's the addition of an IR that signifies a robust skills gap between 'amateurs' and true 'professionals.' Though even that is no guarantee!
There have been far too many helicopter accidents, ATPL/CPL/PPL involving needless 'VFR' flight in non-VFR weather. Helicopters (or those flying them?) simply lend themselves to placing people into situations where options rapidly, completely disappear.
I am unaware of the icing clearance of the AS355, the icing level on the day, and the exact qualifications/experience of the pilot. Maybe these could have been significant?
As a professional pilot all my life, I would never ever be a passenger in any aircraft piloted by a 'hobby pilot' (much less a wealthy one's own aircraft) unless the weather was unambiguously perfect!
Sorry. I may well be alone in that view?
Nobody can yet know whether weather was a factor here.