How could one reasonably produce publicly available documentation where someone refused to execute an unlawful order? Why would someone issue such an order in the first place?
Think about what could possibly motivate a soldier's action: the consequences of questioning an order are far less severe than the consequences of executing an unlawful order. "I was only following orders" has long been discredited as a legal defense.
> Parent is sceptical because of priori contrary evidence that military actions and morals conflict frequently.
Morals are not universal. To which morals are you referring specifically? Some people are morally opposed to violence in principle, the military obviously is not.
[Edit]
I'm still in disagreement as to the logic of the question, but I am beginning to think that the mere existence of court martials in the interest of upholding military law (ie, codified morals of the military) should be sufficient proof that a military body can exhibit a strong sense of morality.
To use an extreme example: I can ask for a examples where someone has committed murder, but it would be unreasonable to ask for examples where someone hasn't committed murder.
There's an asymmetry to showing morality or immorality. Exhibiting a sense of morality is the standard case, and it's hard to show it. Being immoral, however, can be trivially shown by pointing out the mos or law being broken by a specific behavior.