You have not dealt with the VA recently have you?
Right now it is about 50/50.
We keep copies of everything because the VA is quite capable of lying right to your face until you pull out the letter they sent you and show them.
Is the VA the only section of the military that keeps records?
Does she not have any paperwork from her period in the service?
I have no doubt VA could lose records, just seems like there would be other ways for her to prove she was in the military.