Only just found this thread. I wish I'd discovered it a long time ago. OP, you are not evil. Not at all.
Every morning I hope that today will be the day I get the phone call from the nursing home to say my mother died in the night. Not so long ago, DH came home from work early; he messaged me to say that he was on his way as he'd been taken ill, but I didn't get the message, and when I saw him walking up the garden path I thought she had died and he'd been contacted at work. My immediate reaction was, "Oh, at last - it's over..."
My DF died nearly 20 years ago, and all she wants is to be with him. She's bedridden, doubly incontinent, pretty much paralysed on one side, her eyesight and hearing are very poor, and when we visit her all she talks about is how she wishes she was dead and how she hopes every night that she won't wake up in the morning. We (me and DB and my DH, who is an absolute saint and without whom we'd probably both have had a breakdown by now) have tried so hard to find things for her to do, look at, talk about, but it's impossible to divert her...visits are purely duty.
When she does finally go, it will be a relief for all of us.
There, I've said it. And it was very therapeutic, and a little bit scary.