a taste of a great read....read more if you have time.

Why doesn’t God just heal? He does heal, but slowly. Why? God loves each person so much He does not root all that is wrong immediately. If He did, then the structure of our being; body, soul, and spirit, would collapse. We would be mere rubble. Instead, he invites us to be transformed by renewal.
Our physical renewal begins in aging, moves through death, into life. We can, justly, put of this process, but not stop it, because the problems in our physical nature run too deep for superficial cures.
The same applies to our minds and souls. We can be saved, and once saved our healing can begin, but only begin. The problem is too deep for quick cures. You can “pray away” the problems, but only over long periods of time and with great suffering. The final cure, the severe mercy to heal our broken state, is death. We are judged by Christ’s merits, die with Him, and then come to new life.

 http://www.patheos.com/blogs/philosophicalfragments/2013/04/09/my-son-my-son-on-the-death-of-a-child/