The Predator (2018)
Former military members cannot restrained by the VA unless they are proven to be. danger to themselves or others. Even then, they would not be moved to a new facility by a converted prison transport bus. They would be transported by ambulances and using stretchers.
Besides the VA being a completely different department in the Executive Branch of the US government, it wouldn't have the necessary facilities to either restrain, nor to interrogate, a currently serving military member.
The military would have used a clinic or hospital on a military installation as they could "lock it down" and they would be able to hold a military prisoner there.
Incorrectly regarded as goofs
While some National Guard units continued to fly the Huey for many years, by the time of the Third Gulf War, Hueys were no longer used in front line engagements. There would be no way that Nettles would flown for three tours, or any at all in time for him to have returned to the US as a burned out pilot.