Something just occurred to me. I have a "memory" of a family member almost laying on top of me in my bed. It was as if he were doing a pushup on top of me, his body not touching me at all, but posed as if he were going to. Then he seemed to have changed his mind, and left the room.
Now, I actually don't know if that ever happened, or if I dreamed it. Either way, no harm was done, as far as I'm concerned.
My point? Perhaps Dylan had a similar "memory", told her mother about it, and perhaps Mia told her that since she had the memory of it, then yes, indeed it did happen.
Just a thought.
<-----I'M TOTES ROLLING MY EYES