With all the medications she is on, vitamin deletion is highly likely cause. In addition to the adeks you may want to have a naturopath do a vitamin panel to see if she is low in any minerals (especially zinc and copper). You may also want to add oral GSH to her supplement plan.
Also, you may look into daily probiotics to help her gut health and lower inflammation in the gut. This is a must in my opinion for young cfers, especially those who are on antibiotics frequently. Here is a link <a target=_blank class=ftalternatingbarlinklarge href="http://www.cfnutrition4life.com/cfnu/articles.php?cat_id=5
">http://www.cfnutrition4life.co...articles.php?cat_id=5
</a>
I would also consider diet and food allergy if it continues. I have alot of information on food allergies on my site below <a target=_blank class=ftalternatingbarlinklarge href="http://www.cfnutrition4life.com/cfnu/articles.php?cat_id=2.">http://www.cfnutrition4life.co...articles.php?cat_id=2.</a> A traditional allergist can do an ELISA panel which can detect many hidden allergies which can weaken the immune system and cause increased inflammation throughout the body. If you are comfortable with natural/holistic doctors, you could research allergy elimination...it worked for our son who can now eat dairy after 3 years without. It has also helped him with pet and seasonal allergies.
Perhaps these things will help strengthen her immune system naturally and she will gain back her health (maybe get her off some meds too).
Best wishes...hope she is well very soon.