Your love for your children and your desire to see them covered and at peace is deeply moving, and God sees the tears and hears the cries you bring before Him. He invites you to come to Him not in a cold or ritual way, but as a Father, close and intimate. Through Jesus Christ you have been adopted into His family, born again by His Spirit, so you can call Him Father and rest in that living relationship of love. That is the foundation for every other prayer you have prayed.
Scripture teaches that the Lord is your covering and your refuge. To plead the blood of Jesus over your home and your children is to rest in what He has already accomplished for you on the cross, and to ask Him to guard your hearts and minds with His peace that passes understanding. You can ask Him to keep your home under the shadow of His wings, to give quiet and deep rest, and to let His presence fill every room with calm. That peace is not something you must strive to earn, it is the gift He gives to His children who trust Him.
For your son, you can bring his needs before the Father with confidence. Ask the Lord to calm his thoughts and emotions, to quiet fear and confusion and frustration, and to give him a gentle and gracious spirit with the mind of Christ. Pray that God will help him to use the language He has given him to express his needs and feelings in a calm way, and that his sleep would be filled with comfort and joy, free from torment. The Lord delights to give His children rest and to surround them with His loving presence.
For your younger daughter, continue to ask for His healing and protection over her body and mind, for favor in her studies and work, and for uplifting and godly friendships. It is right to pray that in His perfect timing He would bring a godly spouse for her, a marriage that reflects His covenant love, and to ask Him to comfort her heart when she feels the pain of distance from her sister. God can keep her steady and satisfied in His love even when family relationships feel strained.
For your older daughter, your discernment is important. The Bible teaches that marriage is a lifelong covenant between one man and one woman, and that living together outside of that covenant, including sexual intimacy outside of marriage, does not belong to His design. It is not a marriage, even when it is treated as one, and Scripture shows that arrangements outside His design bring jealousy and rivalry and exhaustion and division rather than peace. Just as the record of Jacob's family shows how polygamy brought striving into the home, any relationship that steps outside God's pattern brings confusion and drains self worth.
The influence you describe, with manipulation and control and isolation and conditions being placed on family time and finances, is a sign of bondage, not love. It is right to pray for her deliverance, for her eyes to be opened to truth, for every ungodly tie to be broken, and for her to find the courage to walk away from what is harming her and to return to safety and faith. God often calls His people to return to Him and to their family, as He called Jacob to return to the land of his fathers with the promise, I will be with you. That return is a place of blessing and protection. The story of Lot is a sober reminder that living day after day in a morally polluted environment will wear down a family and cost much, even when a person loves God. It is very hard to remain untouched when the surroundings are corrupt, and the wisest path is to separate from what is corrupting.
God puts a tremendous priority on the family bond and on honoring parents. The first commandment that deals with our relationships with one another is to honor father and mother, and that shows how much He values respect and love within the home. Scripture also teaches that our relationship with God must be made right first. When that vertical relationship is restored and you return to your first love for Him, the other relationships can begin to come back into balance. You can trace many struggles in family relationships back to a need to be more deeply rooted in Him.
In this season, ask God to fill you with wisdom and grace and strength and courage. You do not need to repay manipulation with manipulation. The example of Jacob with his brother Esau, who had vowed to harm him, is that Jacob chose to bless and build up and share and embrace his brother. You can continue to love your daughter, to keep the door open, to speak truth with gentleness and grace, and to maintain healthy boundaries against control and division, while entrusting her fully to the Lord. Pray for the young man and his family too, that any scheme to divide or isolate would be frustrated and that they would turn to focus on what is right before God and release your daughter from this hold.
You can pray with confidence that no weapon formed against you and your family will prosper, not because of your own strength, but because you belong to Him. Ask Him to let His light shine in every dark place, to drive out fear and to guard your hearts. Pray for a year marked by restored unity and laughter and love, for finances blessed so you can help others, and for godly spouses for your daughters in His timing. Above all, keep seeking that close, loving walk with Jesus Himself, and trust that as you draw near to Him, He will be near to you and will lead your family step by step into wholeness.