I do know of a non UPC person that came home one day and saw her deceased MIL sitting on the porch in her rocking chair. She started talking to her. She was also hearing and talking to dead people during the night.
Her husband finally took her to the doctor and in her case, it was due to her hormones being out of balance.
I will say I do not have all the answers to this question.
And of course, there is the debate did Saul actually talk to Samuel or a familiar spirit???
It seems most of these situations reported are from dreams. Dreams very definitely can be from God.
Seeing dead people in your room is a less common experience, I think.
Yeah, slightly!
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Hebrews 13:23 Know ye that our brother Timothy is set at liberty