employee's rights under CA law regarding wrongful termination

California is an "at-will" employment state, meaning that either the employer or employee can terminate the relationship with no liability if there was no contract governing the employment relationship and the employer does not belong to a union. If there was no contract and the employer does not belong to a union, then employment was at will and the employer can fire an employee for good cause, bad cause, or no cause at all. There are certain exceptions to this rule. For example, an employer cannot require an employee to commit an illegal act or be fired. An employer cannot terminate an employee for taking medical leave covered by Federal Law. An employer also cannot discriminate against an employee. In your sister's case, it does not sound like she was discriminated against. However, your sister could speak to a local attorney that offers a free consultation and discuss more specifically the facts of her case.