The military already has access to Grok, but doesn't want it, because it's an inferior model, even compared to open source ones. So the military would probably choose to replace supply chain risk Claude with Qwen or Kimi before Grok.
Grok is according to most benchmarks pretty close to SOTA. It is where the leaders were just a few weeks ago.
Which exactly is best changes on almost a weekly basis as different companies tweak their best model. I doubt the military would want to be switching supplier every week.
It would be untouchable irony for the US to cut all ties with Anthropic and replace them with models developed by Chinese labs. The Onion becomes more irrelevant with each passing day.