Aunt Marge Just Died(You Know She Is her favorite aunt). What Should I Do Now?

This is bad. She's hysterical and there's basically very little you can do to help her. Spending more time with her will be a good idea. However, if your phraseology is wrong, it can be pretty deadly. (Not just for Aunt Marge!)

A typical answer would be, She's passed on. Take it easy, we can't bring the dead back to life.
This answer doesn't help her. She is feeling depressed and helpless. Guess what? You are enforcing her emotions!

How do you help her? If you are already having sex with her, it is good to have sex again. That isn't a better way to celebrate being alive than having sex. Action speaks the loudest after all. Bring her some more tissue after sex. She might continue crying after that. But, don't worry, because having sex increases endorphin (A hormone that makes people happy), your task of comforting her is completed and you get sex!

But, if you aren't having sex with her on a regular basis, you can offer an answer like, Aunt Marge is gone. But, I am here! If you feel the need to tell Aunt Marge anything, I am glad to be your listening ear.