I think you're brave. It's so hard to deal with things like this, and I can't help but think that your sister is trying to go about like things are normal. Perhaps it is denial - people deal with grief and even things that happen around them in different ways. It's also normal for you to be angry. You're doing the best you can with something that's so heavy on your heart. Your sister, I hope, will come around to what is going on. In the meantime...But it's good to give yourself, and your sister, a break.

I'm sorry for what you are going through.