I might be the only one who likes seeing evil karakade spirit coming around Kade and Date love story. And I understand why the script writer did that. It's karma (sin) in Buddhism..
It's her Karma that she is unable to go to reborn directly. Her spirit is still not in peace eventhough Kade helps to do merit for karakade everyday. To a certain extent, those merits helps her a bit to not feeling burning but not entirely. It's her karma that her spirit has to be there witnessing Kade and Date getting married.
As everyone said, what she can do is to surrender and let go which she will do first thing in ep 11 (this is spoiler
). Though she willingly give up and give her blessing to Kade marriage, her spirit will still be hanging there...Again it's karma. When the time comes, she'll be able to reborn. Some people said she is supposed to be living in hell not at the house but we have heard about ghosts having no home and wandering around, right? I can't say much more coz no one knows this for real. It's complicated.