This is typical of a graphics card issue. If you search the forum for 'wireframe', you'll find other reports. What version of SketchUp is she using? If SU2016 or older, turning off Hardware Acceleration in Preferences>OpenGL will probably take care of it. What is the graphics card? She should make sure the drivers are up to date.
Inspecting mirrors is a job I could easily see myself doing.
If you are the smartest person in the room, you are in the wrong room.