I always start this kind of client with training how to do RSA breathing to move her into parasympathetic mode, using something like EmWave (a product from HeartMath) to provide her feedback in the direction of heart-rate variability training, and HEG for a session or two while you are getting a training plan for the EEG.

Chances are that a person with adrenal fatigue has had so much cortisol in her temporals for so long that they look like Swiss cheese, and she is suffering lots of memory problems.  Rebuilding cortisol production may not be a great idea until she actually begins to shift back out of her sympathetic arousal.

The assessment will tell you which patterns are related to keeping her in that state. She may have hot temporals or right/left reversals or front/back reversals or high levels of fastwave coherence or a burnt out cingulate or a variety of other things.

Some dietary supplements help to rebuild adrenal function.  B vitamins are very important.