Keep appropriate careers in mind. If your student starts to show significant progress and interest in music, you'll want to help her on the path to a career that she can succeed in as someone who is visually impaired. This will largely mean steering her away from careers that require sight-reading music on the spot (such as studio music and short-call freelance instrumental gigging) and towards careers where it's more acceptable to learn by ear, such as jazz and vocal music.
Recreate your student's experience in your own practice time. Practice the instrument(s) you're teaching with your eyes closed and rethink how you can describe the playing process in terms of sound, rather than sight. Pay special attention to aspects of playing and handling you would normally describe in exclusively visual terms, such as assembling the instrument, properly holding it, and locating keys or positions.
Teach the student to play by ear. Take him through the standard progressive lessons as you would for other students, but teach these by playing the passage for your student and asking him to mimic it (initially, you will also need to help by pointing out keys and positions for notes). For assignments between lessons, make him a recording of his assignments to learn on his own.
Make use of braille music notation and raised ink printers, if possible, and teach your student to read music. While sight-reading sheet music in performance or group rehearsal is unlikely to be an option (except in the case of vocalists), taking advantage of these options will give your student the opportunity to learn music on her own, giving her the chance to play newly-composed music or learn parts without improvising or needing to mimic another musician's recording.