I think she has been on the otherside since she was very young. I also wonder if we would ever see her mother again.
P/s: I know that she is dead, but I got a feeling that the fallen of her family is caused by the otherside that her mother is a member of the organization which has been researching it. And maybe, like other horror stories, this is an infinite loop that pass down to various generation of her house? If so then yuri seems to be a key to break this cursed loop.