We are truly sorry to hear about the immigration challenges and marriage concerns your children are facing. We will stand with you in prayer and offer some biblical encouragement. Let's also remember that God is sovereign over all nations and their leaders. He can move the hearts of kings (or governments) like rivers of water (Proverbs 21:1 WEB).
Firstly, we should remember Jesus as the only way to the Father. It's important we only pray in the name of Jesus as it is only through the name Jesus Christ that we are even heard by God. So let us pray.
Father, in the mighty name of Jesus Christ, we come to You, the King of all kings, the Lord of all lords, asking for Your divine intervention in the immigration challenges and marriage situations of our children. We pray for godly spouses and marriages that honor You, Lord. We ask that You soften the hearts of the immigration authorities and grant favor to our children. We pray that You will fight for them, and they will be still and know that You are God (Exodus 14:14, Psalm 46:10 WEB).
Now, let's address the marriages. We pray for their spouses, that they may be strengthened in the Lord and in the power of His might. We pray that their love may abound more and more in knowledge and depth of insight, so that they may discern what is best and be pure and blameless until the day of Christ, filled with the fruit of righteousness that comes through Jesus Christ to the glory and praise of God (Philippians 1:9-11, 1 Thessalonians 3:12-13 WEB).
Let us also remember that our true citizenship is in heaven (Philippians 3:20 WEB), and our ultimate hope is in Jesus Christ, not in our earthly circumstances.
In case the children of the one posting this request are in a boyfriend or girlfriend relationship rather than marriage, we must rebuke that. Any intimacy and sex outside marriage is fornication. Also, boyfriend and girlfriend relationships should be considered as courtship with the goal being marriage to another Christian Believer.
Lastly, we must remember the importance of praying in line with God's will. It is only in praying His will be done that we can ask anything according to his will, he hears us. And if we know that he hears us - whatever we ask - we know that we have what we asked of him. (1 John 5:14-15 WEB)
If we do not ask in the name of Jesus, then we do not have any access to God. It is only by the name of Jesus that we can be saved. (Acts 4:12 WEB) We must beware of generic prayers and those not specifically asking in the name of Jesus.
Let us also pray for the one posting this request.
In Jesus Christ's mighty name we pray. Amen.