The will of God is revealed in the Bible. We can not use our experiences or lack of results to explain the will of God. We must base ALL our teaching on the Bible only.

John 10:11 (KJV)

I am the good shepherd: the good shepherd giveth his life for the sheep.

Jesus purchased your healing by dying on the cross for your sins.
He died for ALL your sins and diseases. He did not die just for certain sins and diseases.

When somebody came to Jesus for healing, he did not sort them according to who should get healed and who should not get healed for some reason or another.

Jesus also never referred somebody to a doctor or to use medicine, herbs or other means. HE JUST HEALED THEM.

Some examples:

The boy who had a dumb & deaf spirit

Mark 9:17-29 (KJV)
And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit;

And wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away: and I spake to thy disciples that they should cast him out; and they could not.

He answereth him, and saith, O faithless generation, how long shall I be with you? how long shall I suffer you? bring him unto me.

And they brought him unto him: and when he saw him, straightway the spirit tare him; and he fell on the ground, and wallowed foaming.

And he (Jesus) asked his father, How long is it ago since this came unto him? And he said, Of a child. And ofttimes it hath cast him into the fire, and into the waters, to destroy him: but if thou canst do any thing, have compassion on us, and help us.

Jesus said unto him, If thou canst believe, all things are possible to him that believeth. And straightway the father of the child cried out, and said with tears, Lord, I believe; help thou mine unbelief*.

When Jesus saw that the people came running together, he rebuked the foul spirit, saying unto him, Thou dumb and deaf spirit, I charge thee, come out of him, and enter no more into him.

And the spirit cried, and rent him sore, and came out of him: and he was as one dead; insomuch that many said, He is dead. But Jesus took him by the hand, and lifted him up; and he arose.

And when he was come into the house, his disciples asked him privately, Why could not we cast him out? And he said unto them, This kind can come forth by nothing, but by prayer and fasting*.

We must realize we can not blame God when healing does not take place..

The only time someone wasn’t healed in the Bible (gospels) is when the disciples (Peter, James and John was not there but was with Jesus on the mountain) prayed for them. If Peter, James and John had been there the outcome might had been different.

Right before this incident Peter, James and John had been with Jesus on the mountain where they witnessed Elias and Moses appeared and talking to Jesus.

* When Jesus said “This kind can come forth by nothing, but by prayer and fasting” HE did not refer to the boy and the evil spirit. He referred to the unbelief of the disciples. 

If prayer and fasting is the reason why that particular disease could not been healed, that means that every other disease can be healed without prayer and fasting. Why? Because Jesus never referred to prayer and fasting in any other place in the Bible.

If there is unbelief in the one that are praying, the Authority and Power of The Holy Spirit is limited.

* Unbeliefe
apistia: unbelief
Original Word: ἀπιστία, ας, ἡ
Part of Speech: Noun, Feminine
Transliteration: apistia
Phonetic Spelling: (ap-is-tee'-ah)
Definition: unbelief, unfaithfulness, distrust.

Was it the will of God to heal the sick boy when the disciples prayed for him?

Of course it was the will of God to heal him! Jesus showed us clearly the will of God in the Bible.

Jesus healed everybody that came to him. So it should be with us.
Matthew 4:23, Matthew 8:16, Acts 10:38

If you are willing..

Luke 5:12-13

While Jesus was in one of the towns, a man came along who was covered with leprosy. When he saw Jesus, he fell facedown and begged Him, “Lord, if You are willing, You can make me clean.” Jesus reached out His hand and touched the man. “I am willing,” He said, “be clean!” And immediately the leprosy left him.

This man knew that Jesus could heal him. But he was not sure that Jesus would heal him.

Jesus is our example

Don’t look for anything except for one person to be your example, namely Jesus and his example in life and healing.

God can heal you, and it's also the will of God to heal you.