Can you reframe the issue with your husband? In the military, there are three key types of leadership: direct, operational and strategic. As parents, we face the difficult task of integrating all three. We have to understand that there can be mission failures without disregarding operations altogether, even if it sets them back, and most often missions are not critical to our overall strategy. We build success through non linear approaches. We understand there will be wins, losses and plateaus. We build relationships with the everyone, and we succeed slowly - often led by diplomatic overtures, with support provided by subtle intervention and on occasion the more overt.
You share a strategic view of what you want for, and with, your son. He is old enough to be part of the picture. You want him to be happy, successful, kind. How do you achieve that? Long run political choices, avoiding entering into costly battles of attrition, and investing in institutions that facilitate his success.
If your husband wants to parent like a military man as that is so central to his identity, he should do so in a successful manner. We aren’t fighting in trenches anymore, so no wonder he’s losing on all fronts. If he can’t act pragmatically and turn toward a superior approach, then you and your son will cut your losses - faced with an ally too keen on friendly fire and unacceptable losses - and leave.
I’m sorry you’re stuck in the middle, I have a lot of sympathy for both you and your son 