So I'm a 19-year-old man, and I have a 12-year-old sister. For over a year, her attitude has gotten worse because she barely speaks to anyone at her school, and when things don't go her way, she immediately resorts to violence such as hitting her friends in school. My parents always resort to yelling or maybe hitting when dealing with it, and it doesn't have any effect on my sister's attitude. If things go like this, my sister's attitude could take a turn for the worse in the future. Can you please give me some advice so that I can help with my sister's attitude so that she can have a better life?