It's pure fearmongering, US cannot quit NATO because it's a pillar of US imperialism. The only purpose is to blackmail EU governments to pour more money and to deepthroat the boot farther.
Realistically though, what would change in practical terms if US quit NATO. Europe made itself entirely dependent on US at this point, and they're terrified of Russia. So, they're still going to be buying weapons from US, and they're still going to be economically subjugated by US because they don't have other options. Seems like leaving NATO would just give US more flexibility to focus on Asia while making Europe more desperate which keeps it firmly under US control.
I can certainly see EU going full fascist. The two main problems EU has are lack of energy and lack of industry. There aren't any simple solutions to these problems either, and the industry problem can't even begin to be tackled before the energy problem is solved. I expect that for the foreseeable future EU is going to be forced to rely on US for protection.
What we might see though is countries exiting the EU in favor of joining BRICS. Hungary and Slovakia seem like possible candidates here. Doing that would restore their access to Russian energy and Chinese manufacturing, and that will likely provide a much better economic stimulus than anything EU can offer.