You would think it would be an implied contract or agreement, meaning the implication was that this particular job was there for her when she returned; so a breach of contract / possible discrimination may have occured.
I am not a Lawyer tho nor do I have IR qualifications.
Does she have a Union she could contact? Even if she is not a member she can talk to a Union (Miscellaneous Workers Union???) who would probably be more than willing to offer her some help or advice.
My advice would be to have her get some proper advice before she takes it any further.
