Mike,

I need biblical insight on this, so can you help me please. I have a relative who says she sees dead people and they tell her things. All I know is that the dead are asleep according to scripture. But can demons appear as a dead relative and decieve?

Your brother in CHRIST,
H____

Hi H____,
Yes, indeed, demons can appear as a dead relative, but as you mention “the dead know not anything:

Ecc 9:5  For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten.

That is exactly what happened when King Saul sought to correspond with the dead prophet, Samuel:

1Sa 28:7  Then said Saul unto his servants, Seek me a woman that hath a familiar spirit, that I may go to her, and enquire of her. And his servants said to him, Behold, [ there is] a woman that hath a familiar spirit at Endor.
1Sa 28:8  And Saul disguised himself, and put on other raiment, and he went, and two men with him, and they came to the woman by night: and he said, I pray thee, divine unto me by the familiar spirit, and bring me [ him] up, whom I shall name unto thee.
1Sa 28:9  And the woman said unto him, Behold, thou knowest what Saul hath done, how he hath cut off those that have familiar spirits, and the wizards, out of the land: wherefore then layest thou a snare for my life, to cause me to die?
1Sa 28:10  And Saul sware to her by the LORD, saying, [ As] the LORD liveth, there shall no punishment happen to thee for this thing.
1Sa 28:11  Then said the woman, Whom shall I bring up unto thee? And he said, Bring me up Samuel.
1Sa 28:12  And when the woman saw Samuel, she cried with a loud voice: and the woman spake to Saul, saying, Why hast thou deceived me? for thou [ art] Saul.
1Sa 28:13  And the king said unto her, Be not afraid: for what sawest thou? And the woman said unto Saul, I saw gods ascending out of the earth.
1Sa 28:14  And he said unto her, What form [ is] he of? And she said, An old man cometh up; and he [ is] covered with a mantle. And Saul perceived that it [ was] Samuel, and he stooped with [ his] face to the ground, and bowed himself.
1Sa 28:15  And Samuel said to Saul, Why hast thou disquieted me, to bring me up? And Saul answered, I am sore distressed; for the Philistines make war against me, and God is departed from me, and answereth me no more, neither by prophets, nor by dreams: therefore I have called thee, that thou mayest make known unto me what I shall do.

“Saul perceived that it was Samuel.” King Saul never even got to see the apparition which claimed to be Samuel. This woman was a witch who God was dealing with “according to the idols of her heart,” and the Lord Himself was deceiving both her and King Saul, not with the message which this evil spirit brought, but with the means of delivering that message via a witch who claimed to be able to speak with dead people.  Here is what the scriptures teach about such deceptions which result from those who come to God’s word to find what they have already decided is in God’s word; things like the dead know what is in the future:

Eze 14:1  Then came certain of the elders of Israel unto me, and sat before me.
Eze 14:2  And the word of the LORD came unto me, saying,
Eze 14:3  Son of man, these men have set up their idols in their heart, and put the stumblingblock of their iniquity before their face: should I be enquired of at all by them?
Eze 14:4  Therefore speak unto them, and say unto them, Thus saith the Lord GOD; Every man of the house of Israel that setteth up his idols in his heart, and putteth the stumblingblock of his iniquity before his face, and cometh to the prophet; I the LORD will answer him that cometh according to the multitude of his idols;

These “elders of Israel” had come to Ezekiel to hear what they wanted to hear, not what Ezekiel had been told by God to say. Here is who God tells us has so deceived those who come to His Word seeking to make it say what they want it to say:

Eze 14:7  For every one of the house of Israel, or of the stranger that sojourneth in Israel, which separateth himself from me, and setteth up his idols in his heart, and putteth the stumblingblock of his iniquity before his face, and cometh to a prophet to enquire of him concerning me; I the LORD will answer him by myself:
Eze 14:8  And I will set my face against that man, and will make him a sign and a proverb, and I will cut him off from the midst of my people; and ye shall know that I am the LORD.
Eze 14:9  And if the prophet be deceived when he hath spoken a thing, I the LORD have deceived that prophet, and I will stretch out my hand upon him, and will destroy him from the midst of my people Israel.

Attempting to communicate with dead people who know nothing is certainly “separating oneself from God” and is the result of being deceived by the Lord Himself. “I the Lord have deceived that prophet.”
These elders of Israel were like people to day, and like the witch of Endor and like King Saul, who could care less that God had forbidden His people from attempting to communicate with those who “know not anything.” That is right, God had already forbidden such nonsense, but those who ignore the truth are susceptible to such nonsense, despite the clear words of God to the contrary:

Deu 18:10  There shall not be found among you any one that maketh his son or his daughter to pass through the fire, or that useth divination, or an observer of times, or an enchanter, or a witch,
Deu 18:11  Or a charmer, or a consulter with familiar spirits, or a wizard, or a necromancer. [ One who claims to communicates with the dead]
Deu 18:12  For all that do these things are an abomination unto the LORD: and because of these abominations the LORD thy God doth drive them out from before thee.

All who attempt to communicate with the dead “are an abomination unto the Lord.” So do not get involved in such abominable practices. I hope this is of some help to you.

Your brother in Christ,
Mike