Eliphaz flows with so much thought, speculation, and proverb that in one paragraph his flow of reason may turn upon itself (ie: 5:1-7). I cannot answer every point he make, and I'm not sure it would be the thing to do unless any particular point becomes a stumbling block to someone.
A couple of things stand out to me. Maybe someone who is wiser than I can continue this discussion to everyone's benefit.
Where is your hope?
Eliphaz answers Job's lament of suffering. (Job 4:2-6) As John Bunyan's Ignorance hoped that his good thoughts and ways saved him, Eliphaz points out Job's good works. He states boldly that Job's hope ought to be in his good works. "Should not your piety be your confidence and your blameless ways your hope?" (v.6) After pointing out Job's righteousness and urging Job to cling to it for hope, he then points out that the innocent never perish; this in the face of what Job has suffered. I'm just not sure where he is going with this, and it might be that he had not (in the seven days of silence) thought it out thoroughly.
Test the spirits.
Job 5:12-21 kind of makes me think of Joseph Smith and Mohammed. Who was it that visited Joseph Smith? Who visited Mohammed? I do not think that they were lying. I think they saw someone, but who (this is my theory...not to be confused with knowledge)? Was Eliphaz also visited by a spirit? It was not a spirit of truth. Was he just saying that he was visited by a spirit to give his words more weight?
Clouds without rain
In Job 4:17-21 Eliphaz goes on with his intellectual theology. This is very palatable stuff. but it seems to be irrelevant to the situation at best.
Rather than expose my ignorance, I will stop for now. I will, as time permits look into commentaries and I hope someone will also add comments to help me to understand better.
Please keep in mind that I have never dug into Job 3 - 37 and I am commenting based on my knowledge that God answered in later chapters.