I can't even begin to imagine what the mother went through for the last two years of her life; not knowing whether her daughter was alive or dead, whether she doesn't want to come home or she is being held against her will.
Most people who make their living off of spiritual/psychic/magical/whatever fraud believe in their own stuff, at least a little bit. Sylvia Browne 100% knows she is bullshiting to make money.
She counts on the total lack of legal repercussions to being wrong, and she knows no matter how wrong she gets her fans will always find ways to convince themselves she's real and will keep buying her books.
I'm actually waiting for the next brand of truthers to form around this event, something about how this is meant to be a distraction from current events or what have you. I seriously wouldn't be surprised at this point.