We truly understand your concern as a parent, and it's commendable that you're seeking God's will in this situation. Let's turn to the scriptures and pray together for God's guidance and confirmation.
Firstly, it's important to note that God's will is always revealed through His Word, the Bible. In matters of relationships and marriage, God has given us clear principles. One such principle is that marriage is a lifelong commitment and should not be entered into lightly or hastily. It is also important for Christians to marry other Christians as is evident in the scripture, Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness? (2 Corinthians 6:14 WEB).
The fact that your son and his girlfriend have only known each other in person for three months is a valid concern. While it is possible for God to reveal His will in a short period, it's also important to test the spirits to see if they are from God (1 John 4:1 WEB). The Bible tells us to be sober-minded and watchful because our adversary, the devil, prowls around like a roaring lion, seeking someone to devour (1 Peter 5:8 WEB). Therefore we should not be quick to believe his assurance that God has confirmed their marriage is His will.
It's also crucial to consider that God's will is often confirmed through a peace that surpasses all understanding (Philippians 4:7 WEB). This is a peace that should be felt by all parties involved, including you, the parents. If you're seeing red flags and feeling uneasy, it's important to pay attention to these feelings and continue to seek God's will.
The Bible tells us, Trust in Yahweh with all your heart, and don't lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight (Proverbs 3:5-6 WEB). We need to encourage your son to continue to trust in God and acknowledge Him in all his ways, including this relationship.
The scripture also tells us, Children, obey your parents in the Lord, for this is right. Honor your father and mother, which is the first commandment with a promise, that it may be well with you, and that you may live long on the earth (Ephesians 6:1-3 WEB). Your son should consider your concerns and seek to honor you as his parents.
Let's pray together:
Dear Heavenly Father,
We come before You today, seeking Your will for your son Franco's life. We ask, Lord, that You would reveal Your will clearly to him regarding his relationship and potential marriage. Help him to test the spirits and discern Your true will.
Lord, we also ask for wisdom and discernment for you, Franco's parents. Help you to guide him and provide him with godly counsel. Give you a peace that surpasses all understanding as you trust in God and acknowledge Him in all your ways.
We pray that Franco and his girlfriend would seek Your will above all else. Help them to honor You and their parents in this relationship. Give them wisdom and discernment as they navigate this decision.
In Jesus' name, we pray. Amen.
Encourage your son to continue to seek God's will and consider your concerns. He should be open to godly counsel and be willing to wait on God's timing. Remind him that God's will is always for our good and His glory.
Let's lift up Krzeomar's children for godly spouses and the blessing of children. "Delight yourself in the Lord, and he will give you the desires of your heart" (Ps 37:4). Trusting Jesus for their future families. In Jesus' name! 
Let's lift up our fellow members in prayer! 
**Prayer Updates!** 
