Well can you take some of it back!?
Some people can't use heavy moisturizers - she probably has fine strands. Sounds like her hair is like mine and has a "weak" curl pattern with fine strands. You have to make sure that the protein moisture balance is right or else the hair will be frizzy and curls won't stay. Try a protein treatment, even if she doesn't need it her hair may like it. I personally always get really strong bouncy curls after a protein treatment. But she'll probably still need a lot of hold in products especially in the summer. A heavy leave-in can cancel out the hold so if what she's been using works stick with it or get similar products. Don't worry some people just don't need the heavy stuff all the time. I only use butters as deep treatments or pre-wash and use minimum leave-in in the summer.
Has she been able to use the Shea Moisture or similar products before?
What else did you buy?