Basic Remote Desktop test
What happens if she goes to the CanYouSeeMe site and test on port 3389?
Have you tested over her local LAN, if she has one, to see if you can connect using RDC from another local computer? Use the local static LAN IP of her RDC host when calling from the other local RDC client machine. See the diagram...
As an interim workaround you might have her download and install TeamViewer.