I'm a Christian and I have to say...that mother is waaaaaaaaaaaay off. Doesn't she know her Bible better than that? 1 Samuel 28 [Here in an online version...
http://www.biblegateway.com/passage/?search=1 Samuel 28;&version=31;] has the story of Saul and the Witch of Endor. Saul wants her to raise up the spirit of the dead prophet Samuel. When she goes to bring up her 'familiar' (the spirit that she always consults for answers, some might say her regular devil or demon), she is terrified because the actual spirit of Samuel is brought up. Samuel and Saul have a conversation about a battle taking place on the next day, with Samuel predicting Saul's and his sons' deaths.
So, the Bible is stating it's possible for an actual spirit to be out and about, to be recognized by the living and for the spirit of a dead person to converse with the living.
And this mother on PK calls herself a Christian and would probably profess to believe in the Bible.
So ghosts/spirits are a Biblical reality that she refuses to acknowledge.
agnes!