I actually ran across that and read the relevant section when googling earlier in this thread. To me it seemed unclear what his motivations allegiances were, just that enough people were worried that he was a piece on the board that could cause problems that he was removed from it. That doesn't mean it was likely, it just means that they didn't want to deal with the complications of having to think about it at all would entail, or to worry about players that would be enticed by it, etc. I imagine in a time of way you try to reduce complexities and unknown as much as possible. Even if a few people have concern over him, it may be easier to just ship him away and appease anyone's concerns if he's not meaningfully important to the war effort. He was made a major-general, but how much experience he had in that role and how good he was performing in it is unknown to me, but I suspect it was at least partially honorific or nepotism whether from the top down or emergent (do I promote the royal or the unknown? Which is safer for my career...).

But that's all during the war, and with one individual of the royals, and I would think the rest of the royals would not be happy going forward with the Nazis thinking they could mess with the line of succession/assassinate they King.