Parents who have several children often do their best to treat them equally. However, that doesn’t always mean they should receive the same exact thing. Each child has unique needs, so arguably, they require different things from their parents.
This brother seems to disagree with this, as he felt it was unfair that he had to pay rent while living with his parents when his little sister didn’t. The family tried to explain that their situations were completely different, which he refused to believe, continuing to provoke his younger sibling.