A little bit of more information would help.. Are they ' messing' with her? Does she think they can harm her in any way? Did she ever felt a touch, a cold breath on her cheek or other body part?
But anyway.First, like it's mentione above, you should ask them to leave ( Kindly! When dealing with spirits the first mistake is to have a bad attitude, this just " shakes " them up and makes them angry. Always be kind, and try not to show fear. ). Tell them it's time to move on, or that they can not stay in that house.
If after that, they come back or refuse to leave, try again, say it's your house and that they can not stay there. If they pose a threat, do a banishment/cleansing spell on the house. Sage is a good tool when dealing with negative energy.
HOWEVER, if they do manifest physically, like she waking up with bruises or scratched, feeling hands passing through her hair or something like that, you should get out of the house. This kind of spirits are extreamly bad also may be called " Poltergeists ". These can manifest, either by the smallest thing or do a big one, on the physicall world and can harm her and her family.
Add as much as information has you can please. Do they manifest? Do they pose a threat? Do they only give bad vibes?