The pilot wasn't experienced nor did he have an Instrument Rating and previously had a fright, which should have been a lesson, but not so.
A charter pilot can be - and often is a 250hr pilot with no instrument rating. I don't know the pilot, but based on the news reports he had significantly more experience that that. But we'll know in complete detail when the ATSB releases its report.
I have read nothing about a previous fright, so know nothing of it. And I'd suggest that unless you know this first hand from the deceased pilot, then you don't actually know either.
The flight was not required to be IFR. He had successfully from from Adelaide VFR. Whether or not the take-off was in VFR conditions is a key question that will be addressed by the ATSB. But I reckon that only people who were physically at Mt Gambier at the time know the answer.
But, I think the flight path raises questions about whether fog was the root cause. But until the ATSB report, this is all idle gossip.
I can understand the grief of the husband and father of the passengers. But I don't think its any more or any less than the grief of pilots family. The pilot didn't set out to harm anyone and he was duly qualified by CASA to be safe to conduct such a flight.
There is a lobby that says a Commercial Pilot would be safer. But, speaking as a commercial pilot, a CPL does not create pilots that are necessarily better or safer. The CPL licence is primarily to teach pilots to operate within the environment of working in an environment of commercial operators and operations manuals.
I think that pilots have an unfortunate tendency to be overly critical of other pilots that have accidents and that there is an air that we could have done better. Sometimes this is true, sometimes it is not. I think there are too many unknowns in this accident to pass judgement yet.