Looks like he has a Rolleiflex T.

If you can remove your current screen then you can install the new one.
However, please note: These new screens scratch easily, handle with care.
Also, you may have to calibrate the screen and that is easily done as the two lenses can be adjusted separately. You will need an object on infinity (or a film SLR/lens) and some tape/screen in place of film. Search here and other photo site for detailed steps on the process.

The screens are not cheap and not everyone loves, but if your current screen is dark, they will very much help focusing.