Is it because he is military or because he sides with the goverment, because if its the former the he could still side with the people and in fact be a great asset then.
He just joined the Air Force, so he's have to side with the president.
Assuming they haven't changed the oath of enlistment, then his first and foremost priority and duty is the defense of the US Constitution, which is the physical embodiment of the contract between the people and their government.
Following orders that break the government's contract with the people is downright un-American, unpatriotic, and dishonorable in my book. I'd also consider such orders against the law, making it his duty to
disobey them if such a thing were to happen.
Unfortunately, you'd be hard pressed to find any Airman, Officer or Enlisted, who's even thought to read the Constitution since they joined, yet alone think about how they'd handle themselves in such a situation.
As far as making change goes though, if you haven't gone so far as to write your representatives and hold them accountable for what they do in government, take part in awareness movements and petitions in your area of problems you've seen and changes you want made, or even just plain campaign and run for office yourself, then armed revolution shouldn't even be on the table yet.
And no, merely voting isn't good enough.