This sounds difficult
![Sad Hug](https://i.mysupportforums.org/images/smilies/sad_huggy.gif)
Firstly it’s not your responsibility to take care of your sister.
How is your relationship with your sister? How has it been in the past? Have you had a close bond?
Sorry, a lot of questions I know , but how you respond would affect how you might want to proceed with this. But what I want to stress right now is none of this is your responsibility.