I hope this question isn't too broad to be answered and clear enough (which I have a hard time figuring out by myself).
Context:
In this Earth-like world the society is still quite retrograde in the sciences, research and social development. Some crazy mix of 1800's and 1960's, where the development of nations are too distinct and asymmetrical.
However, all around the world there are strange millennia-old "artifacts" that are actually space ship wreckage that people mostly ignore because they are either completely useless and/or just became one with nature to be indistinguishable from the landscape.
A small village with (not so united) neighborhoods that were being assaulted by military forces to conscript their children to a war that they don't care about (thus, their anti-military mindset) ended up finding a space ship wreck in operational conditions, so they use this opportunity to just fly away from everything. Of course, initially they were reluctant, but after a more violent approach by the army (literally invading and burning their homes, accusing them of treason), they quickly changed their minds.
After that, they found a myriad of problems with the flying space ship (that has built-in manuals/tutorials on how to fix and/or understand the technology) and myriads of other problems with these nations at war. After all, who wouldn't kill for anti-gravity technology? Who wouldn't want the chance to take the upper hand on the war, economy and science?
However, the problem is that they would need to develop a more strict set of rules, discipline, hierarchy and coordination to operate the ship at its full potential and have some chance of survival. An ex-almost-soldier that received some training on the military is trying to convince the crew/villagers to create these strict set of rules that are basically military conduct.
As you can guess, they didn't received that approach with open arms, but they understand that they can't just ignore the dire situation they are in.
The Question:
Taking into consideration their anti-military and anti-war mindset (they will fight for self-defense), what social/psychological strategies could be used for keeping this anti-military crew as close to military doctrine as possible?
For example, in a military fleet, the admiral tells an order and the soldier obeys unless such order is insane or just absurd (like shooting at unarmed civilians, for example);
But in a crew that is basically crossing the line between family and military life, the crewmate/cousin that was designated as the "chief of weapons system" can just complain that "they have an headache", that "they didn't sleep enough" and just start beefing with the self-made admiral.
In the military, if such thing happens, the admiral would just expel the person and replace them with the second in command, and the complainer would receive severe disciplinary action.
In a crew made up of friends and family, how one would do that? They aren't there on their own will and accord, they don't have anywhere to go and no one else to replace this person.
How to keep these people working professionally and with discipline?
One could see this the same way as keeping discipline/professionalism in a crew made up of militia and/or pirates, bandits and so on.