She could also have it chemically straightened from her local salon! That works great. Just make sure she conditions well to keep it from harming her hair!
I have naturally curly hair. I tried that pantene straightening shampoo and conditioner. Over the course of ten weeks or so, my curls left me, but my hair stayed full looking and bouncy. Maybe something like that would help her? It took some time, it didn't happen rightaway.
Remember Susan Powter? Stop the Insanity (She's back with a new exercise series, btw - I love her, she is my fitness mommy, lol) She shaved her head because her hair was like that & she was tired of dealing with it.
On a not so drastic note, a cut like Jamie Lee Curtis' is really cute and would hide a multitude of problems.
She has really weird, combination hair. In the front, it is kinky/curly, and in the back it is straight. She also gets those kinky curly hairs at the base of her neck. It's really annoying for her to say the least! Her question is, should she get it cut? If she does cut it, will it make the back curly or just wavy? She basically feels like she is a "slave to the flat iron" ! Any ideas? Thanks all!
That works great. Just make sure she conditions well to keep it from harming her hair! 
