Is my sister's statement correct that she will not be held accountable for looking at immodestly dressed women, and that there is a difference of opinion among scholars regarding music, and that TV series can be beneficial for showing the consequences of mistakes or for conveying meaningful ideas? And if her words are incorrect, should I boycott her and deal with her harshly?

The legal prohibitions in films and series are not limited to the appearance of nudity but also include promoting evil and beautifying immorality. Abandoning your sister because she watches series is not permissible unless it results in an overriding benefit, such as her ceasing to watch forbidden content. Otherwise, it is not permissible, because abandonment varies according to the abandoners, their strength and weakness, and its purpose is to deter and discipline the abandoned.