God cares about everyone. By allowing modern medicine people that don't believe in Jesus also have an opportunity at being healed. At the same time, Christians, even though they believe God can heal them, have an opportunity to get the care they need if God chooses not to perform a healing miracle in their lives.
With the advancements made in modern medicine minor, and even some major, illnesses can be treated with a simple pill. People can be, and have even been, brought back from the dead. Now this is not to exclude God or imply that He is impotent in power. Instead it should be celebrated that He has graciously allowed these advancements to be made and provided us with the knowledge and resources to do so.
For example, the average person living in the U.S. today lives to be about 78 yrs. old. One of the major contributing factors is the advancement in healthcare. As a Christian, this allows us more time to enjoy our lives and also preach the salvation of Jesus. For a person who is not saved by Jesus, this also allows them more time to enjoy life and to hear the word and avoid judgment. Lost souls who would have normally been terminally ill or have died and been condemned to Hell now can be cured and even brought back from death to live another day to hear the saving Word.
Again, if anything, we see God's grace and mercy by allowing the creation of modern medicine.
But why couldn't God just heal everyone who was prayed for? First, here are millions more non-believers than there are Christians so access to a person with the gift of healing might not be possible (Mark 35). Also, as I stated earlier, not everyone has faith. I would even go as far to say that some people might loathe the idea of being healed by God in that they would then have to acknowledge by their miraculous healing that there is indeed, God.
Ultimately, this thought is not to explain why God does, or doesn't, heal a person. He made us and He can heal us. It is to look at His healing, grace, and mercy in another way.
May the Lord bless you!
Kyle
