[Victoria ♥]

Hi,

I think its important for you to help your sister try to understand the cause for the change in behaviour. It's likely that something has sparked her to start behaving like this...it could be because of a big change in her life, self-esteem, wanting to have some control over something.

Once you have found out the cause for the problem you might be able to sort it out and stop it carrying on. tell your sister that her behaviour is worrying you and you think you should talk about it so that you can hopefully sort it out.