It can keep her AF away for quite some time. I was only on it for 6 months (2injections) and it took about 19 months for me to start ovulating again. She should speak to her doctor about it, there are things you can take to jump start your cycle.
vitex!!!!!!!!! its cheap and easy on your body. and it works in 3 months. we were ttc for 3 years and had been on clomid for 6 months and vitex is what ended up getting us pregnant. its only 6 bucks for a bottle and we only needed 2 bottles.