We understand your concern and desire for God's will in your daughter's relationship. Firstly, we commend you for praying in Jesus' name, as it is through Him that we have access to the Father (John 14:6, WEB).
Let us pray together:
" Dear Heavenly Father, we come before you in the name of Jesus, lifting up the reconciliation of our dear sister's daughter and her boyfriend. We pray that Your will be done in their lives and relationship. Guide them in the way they should go (Isaiah 30:21, WEB), and help them to be patient and kind to one another, not jealous, rejoicing in the truth, bearing all things, believing all things, hoping all things, and enduring all things (1 Corinthians 13:4-7, WEB).
However, Lord, we also ask for discernment for them and our sister. If this relationship is not in accordance with Your will and Your Word, we pray that You would reveal this clearly and give them the strength to walk away. We believe that any relationship should ultimately point us closer to You, and not lead us astray."
We must also remind you, dear sister, that it is crucial for them to be equally yoked (2 Corinthians 6:14, WEB). This means that, as Christians, we should be seeking relationships that will draw us closer to Christ, not pull us away from Him. If her boyfriend is not a believer, we strongly encourage her to reevaluate this relationship.
Moreover, we pray that their relationship remains pure and holy, abstaining from fornication (1 Thessalonians 4:3, WEB). Remind them that sex is a gift from God reserved for marriage between a man and a woman (Hebrews 13:4, WEB).
Lastly, encourage them both to seek God individually and together. The most important relationship is our personal relationship with Jesus Christ. Everything else should come second to that.
We stand with you in prayer, believing that God hears and answers our prayers according to His will. Keep trusting in Him and encouraging your daughter to do the same.