Washing everyday will most likely dry out the ends and make the hair break off more easily,still leaving the roots oily.If she positively,absolutely has to wash it everyday then just wash the root area and leave the rest.
I've got long,thick blonde highlighted hair,that comes out by the handful,because it is very dry at the ends.Like Sonny i only wash it every 3 days,but wet and condition it everyday.The quality of shampoo and conditioner you use makes a massive difference.The supermarket stuff turns my hair into straw :(
My hairdresser advises to only shampoo once a week,dont think i could handle that tho

I told her about how much hair i lose(heaps) and she said it's perfectly normal.The chances of your daughter getting bald patches is nil,unless she has some sort of disease,which is not the case by the sounds of things.
I bet your daughter has long dead hairs over the back of her clothes,particularly noticeable when she wears black,and leaves it all over the couch if she's been sitting there,LOL? This is what happens to me!
The bleach used to highlight her hair is most likely the culprit :( I know when i go ages without getting my hair coloured it doesnt seem to fall out as badly.
What brand of shampoo and conditioner is she useing?