Your prayer to see a heart and mind changed is a right and precious burden to bring before the throne of grace, for the heart is the vital place. Scripture says, My son, give me thine heart, and we know that a heart that is halved is killed. God does not ask for a piece of a heart, He asks for the whole, and He asks it for our benefit and not for His own.
It is God alone who can work this change. Heart disease is a very dangerous disease, and every other part will be affected when the heart is wrong. Physicians can do but little for a weak heart, but the promise stands, Be of good courage, and He shall strengthen your heart, all ye that hope in the Lord. When the truth comes with power, men are pricked in the heart, and that impression becomes operative. Nothing ever pierced my own heart like the discovery of God's boundless love in giving His well beloved Son to die for me. What we need is not merely to be cut to the heart, but to be pricked in the heart by the Spirit, so that the soul cries out for mercy.
Therefore plead not upon any excellence of your own or of the one for whom you pray, but beg for grace upon the terms of grace. Plead His name, for He has a name for pardoning iniquity. You may pray, For Your name's sake, O Lord, pardon and change, and glorify Your fatherly heart by welcoming a prodigal with a kiss of reconciliation. Rely upon Christ who was evidently crucified and who bore sin in His own body, for God will not punish both Substitute and offender for one and the same sin. Underneath are the everlasting arms, and all our needs are provided for in Him.
Be encouraged to pray in the Holy Spirit, which is to pray in fervency and to pray perseveringly. Begging is a hard trade, and a man that succeeds in it must throw his heart into it, and so is praying. Merely to knock at mercy's door without waiting for a reply is like the runaway knocks of idle boys in the street. Wait, I say, on the Lord, and He shall strengthen your heart. He will come punctually at the moment which shall be best for His own glory.
Let us pray together for this dear one you have named before the Lord. Heavenly Father, we ask in the mighty name of Jesus that You would graciously visit this soul, prick the heart, and make it whole in giving itself freely and thoroughly to Christ. Take this heart as it is, though foul and filthy by nature, and make it new, for You alone can strengthen the heart. Turn the mind toward truth, grant repentance and faith, and let Your mercy be glorified in a life yielded to You. We ask this not for our worthiness, but for Your name's sake. Amen.