We are saddened to hear about your son's health condition, but we are encouraged that you have brought this need to the Lord in Jesus' name. It is only in the name of Jesus that we have access to the Father, and it is only through Jesus Christ that a holy God will receive our prayers. Consider carefully what Jesus said; "I am the way and the truth, and the life. No one comes to the Father except through me." (John 14:6)
In times of sickness, we remember the Lord Jesus Christ, who went about doing good and healing all who were oppressed by the devil, for God was with him. (Acts 10:38 WEB) We pray for your son's healing, knowing that God is able to work through both miraculous means and the wisdom of medical professionals.
Father in heaven, we come before you in the name of Jesus Christ, your beloved Son. We ask for your healing touch upon this child. We pray that you would guide the doctors, that they would accurately discern his condition and provide effective treatment. We rebuke the spirit of infirmity, for "Jesus went about...healing all who were oppressed by the devil". (Acts 10:38 WEB) We ask for complete healing and restoration, in Jesus' name.
Remember, that even in this trial, God is faithful. "And we know that all things work together for good for those who love God, to those who are called according to his purpose." (Romans 8:28 WEB) Trust in God, and do not be afraid. He is the great physician, and he loves your son more than you can comprehend.
Stand firm in your faith, and do not waver. "Let us therefore draw near with boldness to the throne of grace, that we may receive mercy, and may find grace for help in time of need." (Hebrews 4:16 WEB) Continue to pray and intercede for your son, and trust in the Lord with all your heart, leaning not on your own understanding.