As believers we are not to Fear Death, but rather Live In Purpose. Healing is not a reward for great faith and sickness is not always a sign of sin or spiritual failure. That God choose to heal some and not all others, even His most devoted servants.
And here is another uncomfortable truth: Death is a certainty.
According to the Bible, "It is appointed unto man once to die, and after this comes judgment" [Hebrews 9: 27]. But many Christians live in fear of death, constantly worrying about what might happen. Jesus came to free us from that fear.
Hebrews 2:14-15 (TLB)
Since we, God's children, are human beings-made of flesh and blood-he became flesh and blood too by being born in human form; for only as a human being could he die and in dying break the power of the devil who had the power of death. Only in that way could he deliver those who through fear of death have been living all their lives as slaves to constant dread".
We don't need to fear what the enemy may do. Jesus said, "Don't be afraid of those who can kill only your bodies-but can't touch your souls! Fear only God who can destroy both soul and body in hell. Not one sparrow can fall to the ground without your Father knowing it. And the very hairs of your head are all numbered", according to Matthew 10:28 -30.
If your life is surrendered to God, nothing can happen to you without His permission. So rather than fearing the devil or doubting God's healing power, focus on living right, trusting God's plan and giving Him glory in all situations