I can understand why you are frustrated with her, because you don't know what is going on inside her thoughts... and I understand that you seem to want to be supportive.

But what you've said in this post? It does not sound very supportive to me. Perhaps your sister feels that as well, which would make her feel worse and more resistant towards listening to your advice.

Particularly when you've told her to get a job - have you just said to get a job, or have you ever (in a nice fashion mind you, not in the sort of tone that you've used in your post) actually helped her look for work or find alternate employment that she hasn't consider as being enjoyable before? Or even found employment agencies to help her look for work? When you just said "***** idiot" that is so incredibly rude and insensitive. If I was your sister and you spoke to me like that....I sure wouldn't listen to a word you had to say. In fact.. my brother DOES speak to me like that and I cut him out of my life a few years ago. And my life? Is actually pretty darn great and I am quite successful in the goals I've set out to achieve!

I think that before you give up on your sister, and before you try to help her recognize the depression that she's going through... you seriously need to evaluate what sort of attitude and persona you demonstrate when you're with her. You could start to looking closely at what you've posted here - can you rewrite the entire MEANING of your post but using kinder, more supportive words?