Jing Han....

Jing Han,
i know its tough on you....
and i know she seems uncontrollable....
And i know you have been tolerating her.....
So asking you to continue to tolerate her seems useless...

But,
there was once this story that i came across.
There was a brother and a sister,
the sister was like your sis,
and the brother was exactly like you,
tolerating all that she does.

But that brother continued tolerating her...
and that really went on for 5years.
All these years, the brother went along with her....
And after 5 years, the sis finally stop going against her brother.
And treated her brother better than how the brother treated her....

I know it is a story only,
and i know you wouldn't do that for her....
Its just a suggestion though...
But maybe your sis has the similar character like the sis in the story,
changes after much tolerance from her brother......