Interesting.
His landing destination was Anoka Airport, next town over from where he crashed. Wouldn’t seem likely to be on autopilot in a landing approach, unless he was not in control for some reason.
Even if he was not on autopilot he could have lost track of his air speed. The ice would have changed the characteristics of the plane. Also That plane had extensive de-icing equipment. But if it was not turned on or functional then things could really go wrong.
The expert also seemed to be saying that the engines on that plane always maintain the same RPM. Changes in power actually come from feathering the prop. I believe that is what I heard.
The problem with that is that the engines sound the same if the throttle is at idle as they do at full power. So it would be easy to forget that your throttles were turned down.