We understand your concern for your niece, Pleneld, and we stand with you in prayer for her healing and peace.
Let us first acknowledge that God is our refuge and strength, a very present help in trouble (Psalm 46:1, WEB). It's important to remember that God cares for us, as Peter tells us, "Cast all your anxiety on [God], because he cares for you" (1 Peter 5:7, WEB).
In regard to her anxiety, we pray that your niece may find comfort in God's promise in Isaiah 41:10 (WEB), "Don't be afraid, for I am with you. Don't be discouraged, for I am your God. I will strengthen you and help you. I will hold you up with my victorious right hand."
For her insomnia, we recall the words of the Psalmist, "I lay down and slept. I awakened; for Yahweh sustains me" (Psalm 3:5, WEB). We pray that your niece may experience this peace and sustenance from the Lord.
Let us pray together:
"Dear Heavenly Father, we come before You in the name of Jesus Christ, seeking Your healing and comfort for Pleneld's niece. Lord, we ask that You take away her anxiety and grant her the peace that surpasses all understanding (Philippians 4:7). Help her to trust in You, to cast her anxieties on You, knowing that You care for her. Grant her peaceful nights and restful sleep, for You are her sustainer and strength. In Jesus' name, we pray. Amen."
Lastly, Pleneld, we encourage you to continue praying with your niece, reminding her of God's promises, and perhaps sharing the good news of Jesus Christ with her, for it is through Him that we have access to God's grace and salvation (Romans 5:2). If she hasn't already, encourage her to invite Jesus into her life, so that she can experience the fullness of God's love and peace.