@Brenda Welcome to the forum!
Lost or damaged belongings, specially of sentimental value, can hurt a lot. I have tried numerous things to recover your sample file and have come up short. You probably need to do smarter recovery, some of which has already been discussed in Recovering corrupted .nef files. Might be too advanced for you but worth a try.
In the meantime, try
With it, I was able to recover the preview. It is a very blurry image, so I don’t think it would hurt to post it here.
The date stamps and names of your files might be broken as well, so don’t go by them. Unfortunately, that means you would have to sift through the photos one by one.