Firstly my heart felt thoughts go out the the friends and family of the pilot missing.
Sadly, having conducted several searches for missing persons and prawn trawlers throughout the straits, I can attest to the difficulty in finding clues as to what has happened. When bad weather and local currents are added to the mix the job becomes even more testing, to the point of putting those involved in searching in harms way.
Having flown AC500's for about 2000hrs I can also confirm it would take a mighty powerful thunderstorm to break one and I'm sure the pilot, who I know, wouldn't have put themselves in such a position. They will fly on one engine quite well and seeing as the flight was going up to Horn the aircraft would most likely have been empty and not full of fuel so the increased MTOW shouldn't have been a factor.
Knowing the pilot involved I agree with MyNameIsIs and don't think pushing a bad situation was high on the list of causes.
As for dodgy VFR, it is rife in the straits and I am also familiar with the Van incident. For christ sake people
there are rules that are designed to reduce the risk of us killing ourselves and each other, not to mention the poor passengers who are non the wiser. If you cant go cos the aircraft isn't up to spec, dont go! if you need to, consider going IFR, if your still not happy, dont go! up there you will only have to wait 10 minutes for it to clear.
Anyways thats a whole other topic.
Wish I could help in the search