The admonition in Job 5 regarding the Lord’s discipline AND his healing hand is from his friend Eliphaz.
In the prior chapter he talks about the swift and sure nature of God’s wrath on trangressors. Bear in mind that Job’s children had been suddenly destroyed. Eliphaz did tell Job in chapter 4 to look to his own integrity (Job’s) and the fact that he (Job) had helped many people as security that God had not forgotten him (Job).
When it comes to losing a child, or children, I can only say that I am confounded. Some things may not be “explained away.” I always go back to the simple concept that I only view events with “eyes of dust” when I have “heavenly eyes” I believe I will understand much more clearly.