Is it possible to fight a chapter 14-12b

This is one of those “an ounce of prevention is worth a pound of cure” situations. The best way to fight patterns of misconduct is not to have patterns of misconduct. It’s like when people ask how to avoid getting kicked out the Army for failing APFTs, we’ll just don’t fail the APFT.

You avoid getting kicked out by doing things that don’t get you kicked out. As my old 1SG used to say, we don’t ask you to do anything that you wouldn’t be expected to do in the civilian world: don’t commit crimes and show up to work

Has he tried not being a habitual turd?

I think it's best to first understand a few things about a Chapter 14-12b. I have dealt with this quite a bit. First, it is not a form of punishment. A 14-12b is an administrative separation. It is basically the Army's way of saying that you are not in the Army's best interest to keep serving. I know it may sound crazy but the Army can fire a Soldier. Just because it is the military it doesn't mean that you have to stay. Next, several leaders will review the company commanders recommendation for the separation and review the grounds of the recommendation. They will decide what is the best interest for the Army. Every packet will be reviewed by legal counsel but they aren't there to stop it or to even fight it. They are there only to ensure that you understand what is going on and to assist you in filing a rebuttal. Very few are retained. You really can't fight because it isn't something that you can fight. I have seen Soldiers open door their commanders all the way up to their BDE commander. It didn't work. Their willingness to be a better Soldier didn't negate their actions that led them to the recommendation.