Liposuction works best on people who are not overweight, but have stubborn areas of fat, which won't go even through diet and exercise.
I had Lipo a few years ago and it was the best thing I ever did. In my family, we carry all our excess fat around the mid sections. No matter how slim I got, I still had a huge stomach. Most of my body would be size 10, but my waist and stomach would remain size 14. Since having it done my body is in proportion and clothes fit me comfortably.
My ex partner was on Prednisilone and it caused very large build up of fat, including the "moon face" look. I know how hard it was for him to lose body fat and even when he got fit, he still had large amounts of fat on his torso.
If your daughter does opt for Lipo, she should do her research carefully and check her surgeon out thoroughly. Ask her GP to reccomment a reputable surgeon. But I would suggest she tries to lose as much weight as she can through diet and exercise and then any stubborn areas can be treated.