OK, so I have a very nerdy, mildly ADHD 9 year old boy who has been fascinated with WW2 for ages. All this started with him getting obsessed with the Titanic when he was about 4, which then led us to look at some old Nat Geo magazines about Robert Ballard's oceanographic expeditions which then led him to get fascinated with the German battleship Bismarck and Operation Rheinubung. The drama of big gun battleships got him in the feels and in the five years since then he has been deeply into naval stuff, particularly WW2 naval combat ever since. Musically this got him into Sabaton and their WW1/2 related metal songs. He actually sat down and watched the 1960s black and white Sink the Bismarck on YouTube, along with stuff like Midway (the version from a few years back). He thinks aircraft carriers are cool and ate up both Top Gun movies and is now getting into submarines (loved The Hunt for Red October) but wistfully repeatedly tries to reason me into agreeing that navies should have stuck with big gun battleships.

However, this has manifested as a deep fascination with Germany in general- he knows the basics about fascism, the Holocaust and Wehrmacht atrocities (but still can't quite get why it happened) but to a small boy I understand the OMG WUNDERWAFFEN attraction. Coincidentally his best friend is an ethnically German girl which further gets him a bit confused because he can't quite grok the difference between "my friend is German, I think German engineering is cool" and "but we still condemn fascism".
To be clear- he understands why racism and prejudice are wrong. As an ethnic minority in our country I suspect he'll come into contact with racial prejudice sooner rather than later so hopefully life experience will lead him away from the alt-right bits of history nerdery.

We're in Singapore, which means there's very little consciousness of the Holocaust in public education- our history syllabus (fairly enough) deals with the Pacific War and its effects on postwar decolonisation when it touches on WW2 whereas the European theatre is just vague background.

I don't know where I'm going with this, really- I like that my son is a history buff, and I don't want to cut him off from intellectual interests he's passionate about but on the other hand I'm wondering how I can let him enjoy this while contextualising it from a progressive perspective.