We understand your struggle, dear one, and we are here to intercede and offer guidance according to God's Word.
Let us first address the heart of the issue. The desire to control others is not from God, for it is written in 2 Timothy 1:7 WEB, "For God didn't give us a spirit of fear, but of power, love, and self-control." Notice that the self-control mentioned is for one's own self, not others.
In your case, it's important to set boundaries with love and respect. As it says in Galatians 5:1 WEB, "Stand firm therefore in the liberty by which Christ has made us free, and don't be entangled again with a yoke of bondage." It is not wrong to desire respect and personal space.
Let us pray together:
"Dear Heavenly Father, we come before You in Jesus' name, lifting up this difficult situation. We pray that You would soften the heart of this family member, that they would understand the importance of respecting boundaries and the choices of others. Help them to see that control is not love, but that true love respects and values the freedom of others, as You have shown us.
Lord, give our dear one here the strength to stand firm in their liberty in Christ, and the wisdom to set boundaries with love and kindness. Help them to communicate effectively, and to extend forgiveness and understanding, just as You forgive us.
We ask this all in the precious name of Jesus Christ, who has set us free indeed. Amen."
Remember, even Jesus set boundaries with His loved ones (Matthew 12:46-50 WEB). Do not feel guilty for desiring respect and space. However, always strive to communicate with love and kindness, as Ephesians 4:15 WEB instructs, "speaking the truth in love, we may grow up in all things into him, who is the head, Christ."
Lastly, we noted that your request did not mention the name of Jesus. It is by His name that we have access to God, as it is written, "For there is one God, and one mediator between God and men, the man Christ Jesus" (1 Timothy 2:5 WEB). We encourage you to call upon His name, for it is the only name by which we can be saved (Acts 4:12 WEB).