We are truly heartsick over the situation your friend is in, and we commend you for being a faithful support to him in his time of need. Let us come before God together, for He is the ultimate healer and redeemer.
Firstly, we must acknowledge that the belief your friend has in a departed spirit keeping him alive is not biblical. It is written in 1 Samuel 28:7-20 that familiar spirits are forbidden by God. We know these can be deceiving spirits that can oppress and harm rather than help. We must pray that any familiar spirits or mental health issues that may be oppressing him be rebuked in Jesus' name.
Let us pray for your friend:
Dear Heavenly Father,
We come before You today, lifting up our dear friend to You. Lord, You know the struggles he faces with addiction, the health issues that plague him, and the spiritual battles he is fighting due to familiar spirits. We pray, Father, that You would deliver him from the bondage of addiction and restore his health. Touch his eyes, Lord, that he may see clearly; heal his memory loss, restore his hearing, and ease his seizures. We rebuke the familiar spirits, mental health issues, and addiction in Jesus' name and ask that You fill him with Your peace and love.
We ask that You reveal Yourself to him, Father, that he may come to know the love of Jesus, trust in Him, and find hope in Him. Send the Holy Spirit to convict his heart and draw him to a saving knowledge of Christ. We pray for his salvation, that he may confess with his mouth that Jesus is Lord and believe in his heart that God raised Him from the dead, for it is with the heart that one believes and is justified, and it is with the mouth that one confesses and is saved Romans 10:9-10 (WEB).
We also lift up our dear sister in Christ who has been faithfully supporting him. Father, grant her rest, strength, a greater capacity to love, and wisdom to know how to be there for him. Guide her steps, Lord, and give her the words to speak that would point her friend to You.
Father, we ask all these things in the mighty name of Jesus Christ, for it is in His name that we have access to You and it is in His name that we are saved. For there is no other name under heaven given among men by which we must be saved Acts 4:12 (WEB) . Amen.
Let us also be mindful of Jesus words: Greater love has no one than this, that someone lay down his life for his friends John 15:13 (WEB).
We encourage you to continue being a support to your friend and to speak the truth of the gospel into his life. Be strong and courageous in the Lord and be assured that we are praying for you both.
Please consider reading the book of John and sharing it with your friend as the Holy Spirit leads.
Remember to be alert for opportunities to share with him the good news of Jesus Christ,
He was in the world, and the world was made through him, and the world did not recognize him. He came to his own, and those who were his own did not receive him. But as many as received him, to them he gave the right to become Gods children, to those who believe in his name: who were born not of blood, nor of the will of the flesh, nor of the will of man, but of God John 1:10-13 (WEB).