I am losing it!

From wake up, until she goes to sleep she complains, that God should let her die. Over and over she calls on him to take her, "straight up, straight up". It used to be she only did this at night, but lately she starts the minute she gets up. It has finally gotten me to the breaking point.
She has never enjoyed life. Even when Dad was alive, she would say to him, " it's time for us to go to our apartment ( mausoleum ) , Papa!" She would say that to him every day, over and over. I think that's why he finally tuned out, and checked out. Now she is doing it to me, and I can't take it any longer. I have never known someone who seems to enjoy being miserable, so much!
She also constantly talks to herself outloud, and when I ask, "what was that?" she tells me to mind my own business. She wasn't talking to me.