The prodigal son chose to take his inheritance, and live his own way in the world. His father gave him his choice. His father did not try to stop him from leaving. The father did not go after him, did not go out looking for him. But he did what our heavenly Father does: look for his son to come back. When his son came back confessing and repenting, he welcomed him back, rejoiced.
Let go, pray for your child/children, spouse, whoever it is. Pray for yourself that God do His work in you also. Be redemptive when they come back seeking your forgiveness.
God is the only one who can change those who want to be changed, save those who want to be delivered from sin. God knows who all will not be saved because they love sin and death more than God: They hate God and love death.
If your child, spouse, whoever wants to leave, they think the grass is better, greener on the other side, they think they have it so bad with you, let them go. God does not force us. We do not force. Christ died for everyone, knowing many would reject Him, hate Him, want no part of Him. The sins of us all put upon Christ—He who knew no sin, still laid down His life for all mankind that we might live. What love is this!
When you give up self and surrender all to God, pray His word to Him; stand still and see the salvation of the LORD. God is always faithful, true. His word will come to pass. Period.
Be ready to receive those who in the past turned away. Be ready to receive those who you in the past have had to let go. If you are praying for them, giving God consent to intervene in their lives; He will. By your faith, by our faith others are healed and made whole.
Maranatha