Tartare,
I assume that slowing down at the sort of altitude that this Squirrel was at when it hit the hill simply isn't an option, because you'd lose lift over the disc and fall out of the sky...?
Most helicopters have a minimum manual control IMC speed, below which controlling the aircraft with sole reference to instruments becomes increasingly difficult. Flying with airspeed above say 40Kt in a helicopter is not remarkably different to a fixed wing, but to decelerate below that speed may require transition to the hover, all of which takes more control coordination of pedals, cyclic and collective while trying to maintain height and heading (hovering is pretty much the most difficult thing to learn about rotary flying). Hovering with sole reference to instruments is not impossible, but you would be stupid to try. The beauty of coming to a standstill and subsequently landing in a helo to avoid bad weather only ever works if you make the decision while you are still VMC.
As for the that popular old perennial of experience, as Crab mentions, it counts for nothing without post qualification instruction and regular checks. I believe the word in use now is "recency" as opposed to "currency" but neither are meaningful without competency, and competency has to be gained, tested and measured in a structured way. Not everyone needs an ATPL to be competent, but a competent pilot sets and knows their personal limits on planning, weather, hazards and manoeuvres whenever they go flying.