How long she is allowed to visit Canada is up to the CBSA officer she encounter at the border. Visitors are often given a default visit of six months. However it's possible to be given a shorter visit (or even denied entry) if the CBSA officer is concerned she lacks tie to her home country or may have plans to remain in Canada long term. When she arrives, she should make sure she packs like a tourist (don't bring so much stuff that it looks like you're moving), make sure she brings evidence of ties to her home country (e.g. property ownership, rental, employment, etc.), and also be able to demonstrate proof that she has the funds required to pay for her visit to Canada.
