Ya, its pretty normal to feel ill from the diet and supplements; that means you have candida and that its working.
She might be having a slight calcium or other mineral deficiency; when your body fights off a major illness, it taps the reserves of your body which includes fats/proteins/carbs, etc and calcium/minerals/iron,etc. That is one the main reasons you lose weight on the diet. Also, fungal invaders could be attacking the body more when you are going through the die-off; there is a fungus that lives underneath the nails of your body, so it could be thriving.
Maybe get a vitamin d, calcium, and magnesium vitamin that has no bad ingredients in it. At the vitamin shoppe, I found only one good brand that didn’t have bad ingredients for this type of vitamin.
I am also taking magnesium chloride; this helps mineralize the calcium in your body to allow for better absorbtion(mispell). My naturopath makes this stuff, so I am unsure if you can get it elsewhere like a vitamin store.
She might want to consider spraying some of the anti-fungals on the nails to see if that makes a difference (I have no idea how effective this is).
Also, when experiencing die-off symptoms, it is best to use a sauna, steam room, or even a hot bath to help remove the toxins from your body. This will almost completely nullify the die off symptoms you may experience.