There are a lot of different types of leukemia and some are very treatable.
First find out what type of leukemia she has then I think you can probably search on google and get some answers. But, basically it is a cancer of the blood cells and the white blood cells in particular do not mature properly and grow a lot of immature cells so while the patient has a lot of white blood cells they are not good ones. They usually have lower red blood cells and lower platelets than normal. So they may be tired, bleed easily and get infections that they have a difficult time getting over.
Here is a little web site about leukemia.
http://rdoctor.com/symptoms_disease/conten t/view/110/2/

How did your friend end up going??

By the sounds of it, it doesnt seem like leukemia but as the above poster said, there are many forms of it!