VMC
I don't see how anyone can seriously suggest that the captain was visual. As a matter of fact, he obviously was not, given what occurred. So the issue is what he believed at the time, and we know that he believed that it was very difficult to tell the difference between the cloud and the ice. The captain did not have to have experienced a whiteout before in order to appreciate the problem (just as he did not have to have flown VMC at night in order to appreciate the problems in that regard).
So why did he purport to be visual? The probable answer is that he was actually relying on the AINS - and the AINS alone, given that he couldn't get the Tower on VHF radio. Was that allowed? Definitely not. So how was he going to get to see the scattered shacks at McMurdo Station ("I prefer here first") for the first time? Pretend to be visual.
PS - That's not defamatory, because the captain is dead. Paul Holmes knows that rule back the front.