I would say these are words of deceit. Eliphaz has an inadequate view of God of which the author of the book is revealing its inadequacy.

Eliphaz (in chapters 4-5) is counseling Job: "You have counseled many in similar circumstances and you should take your own advice (Physician, heal yourself!): Trust in your piety—the Retribution Principle will hold; it is the wicked who perish and the good who don't suffer. Yet from God’s perspective no mortal is righteous; instead you should appeal to God and accept his discipline."

But he is wrong about many things. Chapters 4-27 present the case of the Challenger, of false beliefs and distorted theology. Therefore we must conclude that this night visitor represents more the spirit of deceit than the Spirit of Truth. God is not speaking to Eliphaz for his own self-correction. The flow of the book is a rhetorical legal case against God, evaluating his righteousness and the Retribution Principle. It is not written so that Eliphaz sees the error of his ways, but rather that all of us see the error of judging God negatively on the basis of the Retribution Principle.

[list][*] Eliphaz is appealing to a common ancient Near Eastern philosophy/theology that no one can be righteous from God's perspective (v. 17), which is only an issue if one subscribes to the retribution principle, a theology the book of Job is tearing down.
[*] Also, in v. 6 he claims that if you have done nothing wrong, you have nothing to worry about, which is also incorrect, as if circumstantial prosperity is the only measure they have for vindication.
[*] He is claiming that suffering is justified because the root of suffering is man himself, and if Job will just repent of the sin that has caused this suffering, and trust God, he will be restored to prosperity. This is not a valid theology either.[/list]

If we go through the text piece by piece to catch his flow:

v. 2: Don't get angry with me if I share these thoughts with you. Maybe I shouldn't speak, but I can't help myself.

vv. 3-5: You've counseled many. Listen to your own advice.

6: Eliphaz identifies Job's fear of God as an irrational confidence since his suffering proves he's a sinner and wasn't fearing God! "You claim you haven't done anything wrong, but your suffering shows otherwise (the retribution principle)."

vv. 7-11 articulate the Retribution Principle: "Good people prosper and wicked people suffer. Period. That's how the world works." (It's NOT how the world works, and is one of the main points of the book.) His point is that the truth of the Retribution Principle is as automatic as the instincts of the lion. (But he's wrong about this.)

v. 12-16: The term identifies prophetic visions (2 Sam. 7.17; Joel 2.28; Zech. 13.4) as well as terrifying nightmares (Job 7.14) and sometimes both (Isa. 22.1, 5). Eliphaz is claiming a revelation from God, but the text never affirms that.

17-21: "Can any mortal actually be righteous? Of course not! You're a sinner, Job. Admit it! This is your problem. Even the angels struggle—they're not divine and can't achieve God's perfect holiness."

In other words, his point in vv. 12-21 is that that are so many ways to offend deity that we can never be confident before them. Instead, just recognize that we suffer because we sin. Own up to it, you deserve what you are getting, and repent.

God would not appear to Eliphaz to give him false information. These thoughts are the work of another.

I’ve been noodling Job 4:12-21 for months. I’m wondering if Eliphaz’s vision was from God, and meant for his own self correction, which he misuses to “correct” Job... or a demonic decoy, used to manipulate him into accusing Job of unfaithfulness.

I honestly go back and forth on it!