Whirlybird
Your loyalty to Jennifer Murray is admirable but the options seem to be mechanical failure, running out of gas or CFIT.
If it was mechanical I guess we'd have heard about it by now.
That leaves dry tanks or CFIT.
They'd not long taken off so unless there was a leak, they had gas.
That leaves CFIT which is what the journalist reports the pilot says.
What more facts do you need?
She says 'Still, I had not had the pleasure of a full-on white-out.'
You're a FI, do you think a PPL without an IR should be flying in conditions where a white-out is a real risk?