You have prayed well, asking the Father in the name of His Son. Such prayer is the breath of the soul, and God who gave His own Spirit will not withhold any good thing from those who call upon Him.
Yet understand that the healing you seek, of body, mind, and spirit, comes chiefly through the indwelling of the Holy Spirit. For where the Spirit is, there is Christ; and where Christ is, there is life. The body may be dead because of sin, but the Spirit is life because of righteousness. If this son of yours is Christ’s, and the Spirit dwells in him, then already the root of all restoration is planted within. The Spirit does not merely patch the old man, but renews the spirit of the mind, quietly slaying the deeds of the flesh and quickening the inner man. That is the complete recovery that endures beyond the grave.
Therefore, pray not only for the easing of the outward affliction, but that he may have a willing heart to be mortified in whatever way God permits. To bear sickness patiently, to give thanks through pain, to crucify the love of ease, this is a whole burnt-offering, a martyrdom without blood, and the sword of the Spirit works mightily in such a sacrifice. In this, patience is born, faith is refined, and a peace that surpasses understanding settles over the soul.
Do not fear when you hear “mortifying.” The Spirit gives no deadly wound, but brings life out of death. That same Spirit who raised Christ from the dead will also quicken your son’s mortal frame if it serves God’s glory. But if, for a time, the body must wrestle with weakness, let him not faint. The love of the Spirit is at work, and the law of the Spirit of life in Christ Jesus has already set him free from the law of sin and death. Nothing, no sickness, no decay, can separate him from that love.
So, pray boldly. Ask the Father to fill him with the Spirit, that Christ may be in him, that his body become a living sacrifice, and that the health of his soul shine bright even now. For the Spirit is not far off; He is the very love that moved you to pray. Cease your anxiety, and let this son be devoted to the renewal of the mind. Whosoever thus possesses the Spirit performs no old deed, and in that newness is the truest healing. May the Lord grant him patience, faith, and peace, and in His time, a full return of bodily strength, that he may rise and declare the wonderful works of God.