If God didn't desire Job to be sick and suffer hardship and disease, then why did he? If you say it's his fault or someone else's then you completely miss the point of the book of Job, which is the sovereignty of God. Job did nothing to deserve it and yet God didn't just allow it to happen to Job, he suggested Job to Satan when he asked him "have you considered my servant Job? There is no one on Earth like him."
Now does this mean he doesn't love us? Not at all. Not only did he send his only begotten Son to die in the place of us, but he has promised complete and perfect healing for all eternity, just not in this lifetime. He has promised instead that his people will suffer in this life. This life does not have perfect health, wealth, and prosperity. That's promised in heaven and the exact opposite is promised here. Whenever we suffer or have disease, we know that God has a greater purpose behind it. Romans 8:28 - "For we know that in all things God works for the good of those who love him. Who are called according to his purpose."
Not only this, but God himself says very plainly in his word that he is the cause of our illness and infirmities. Exodus 4:11 - "Who has made man's mouth, or who makes him dumb, or deaf, or seen, or blind? Is it not I, the Lord?" Friend, that's God talking.
Yes, God does sometimes desire us to be sick. Yet he has promised a greater purpose for all of the sickness and suffering and has also promised eternal health, wealth, prosperity, fulfillment and happiness to those who are his. Only a carnal, earthly mind sets its thoughts on what God can give them in this temporal life, rather than be satisfied that they already have everything eternally in the next one. We need to learn patience and longsuffering for his sake, not selfish obsession with perfect bliss and happiness.