Two people in the Catholic charismatic renewal deliverance ministry in my country, who often are used by God in cases needing deliverance, or who refer people on to exorcisms, Have WARNED people to avoid needless contact with people and places where the occult is actively practiced, Why? Because demons affecting those places and people (where satan has been specifically worshipped), those demons can effect kids or christians who come into contact with those places/ people.
I would not allow a child to go to a house where the Occult is practiced, they could easily start playing the ouijii board for fun, or the Bloody Mary spirit calling game,
Be very careful also; catholic exorcists have warned that people in the occult actively curse those who have wronged them, if you forbid your daughter from talking to their daughter they could put a curse on her, (Exorcists have said the main cases of possession they deal with are of: people who were involved in the occult, or who were cursed by the occult).
Get her to wear a blessed Miraculous medal, to protect her from spiritual harm. Pray the Saint Michael prayer with her every day. Pray for that family every day that they will convert from their errors.
Read the two free online ebooks of Larry Cummins, an irish man (still alive), who was called by God into the catholic deliverance ministry, and who relies strongly on the teachings of Fr Robert De Grandis (who was also very active in the healing/ deliverance ministry)
www.larrycummins.ie
The prayers at the end of both of his free online books would be very helpful for you to pray each day for spiritual protection, and for the conversion of that family.