I suggest letting her come out with you while you are watching the TV or on the internet. Ask her to share with you what she remembers about things on TV such as what the commercials looked like or whatever it is. Even details like the type of clothes she remembers or the type of food cartons she had.

Doing basic daily things this way will show her (without telling her) that things are different. You will give her the things alters need to be able to figure out for themselves what the NOW is like:

1) Safety
2) Ability to state their truth without fear of rejection
3) A witness to their experience / reality
4) A place to explore the new world they find themselves in.