First of all, I think it's great you're supporting your friend in this way. So many people who go through this don't have any support, let alone someone as involved as you. I am glad she has someone who is dedicated and compassionate and wants to see her succeed and heal.
Reporting sexual assault is very, very hard and very, very scary, especially when the perpetrator is someone in a position of wealth and power, or at least protected by wealth and power. Very few perps are ever charged and even fewer are ever incarcerated for their actions, especially if, once again, they are in a position of power, and the military is a great position of power. It's very understandable why she'd be hesitant to come forward.
In addition, rape victims, when they do come forward, are usually raked through the coals. They have to tell their story again and again to people who often are not compassionate and maybe don't even believe her. The toll it takes on a person is very taxing. It's understandable why she'd be scared of that.
I know you see it as her "giving up" but it's probably more a matter of self preservation. These things break you and you are never the same again. Reliving it can break you all over again. I hope you can forgive her for not wanting to go through that.
I would follow her lead. You've given her resources and now the ball is in her court. It may be frustrating but it's her choice, in the end, to heal in her own way, and that may be by never revisiting the incident again. You can bring up that it's helpful to other survivors and that may be the case, but it's still her journey and her path to healing. She has to make the choice for herself. All you can do now is show her you still care and support her no matter what she chooses.
Good luck and feel free to
PM me if you need anything.