We join you in praying for your sister and her daughter, and we appreciate your heartfelt concerns. We will address the issues and also discuss the authority of Jesus' name in prayer.
Firstly, it is so important to pray in the name of Jesus. As it says in John 14:6 WEB Jesus said to him, "I am the way, the truth, and the life. No one comes to the Father, except through me." And in John 16:23 WEB "In that day you will no longer ask me anything. Most certainly I tell you, whatever you may ask of the Father in my name, he will give it to you."
Now, let us pray for your sister together. Father, we come before you in the name of Jesus, and we ask that you watch over our sister's sister. Guide her in the right way, Lord, and let no weapon formed against her prosper. Do not let her be around bad influences. Instead, surround her with godly influences that will encourage her to make good choices in life. Open her eyes to see the changes she needs to make to live a better life. Help her to walk closely with You, obeying Your Word and applying it to her life. Help her to be the mother that You want her to be to her daughter. Protect her from temptations.
We pray for her healing—physically, spiritually, and mentally. Let her know that she is deeply loved by You and that You want what is best for her. Cover her with the precious blood of Jesus from the top of her head to the soles of her feet and protect her. Help her to see Your light, Jesus, and let it touch her heart and soul. In the name above all names, Jesus Christ. Amen.
Regarding relationships, we encourage her to surround herself with godly influences and to seek out a godly spouse if she is not already married. We pray that God would bring forth a godly man into her life if that is His will, that they would court each other with the goal of marriage. We rebuke any actions that are not in accordance with God's Word, and we pray for purity and righteousness in all areas of her life.
Encourage her to meditate on Psalm 1 WEB:
Blessed is the man who doesn't walk in the counsel of the wicked, nor stand in the way of sinners, nor sit in the seat of scoffers; but his delight is in Yahweh's law. On his law he meditates day and night. He will be like a tree planted by the streams of water, that brings forth its fruit in its season, whose leaf also doesn't wither. Whatever he does shall prosper. The wicked are not so, but are like the chaff which the wind drives away. Therefore the wicked shall not stand in the judgment, nor sinners in the congregation of the righteous. For Yahweh knows the way of the righteous, but the way of the wicked shall perish.
Also share 2 Chronicles 7:14 WEB:
If my people, who are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land.
Remember, it is only by the name of Jesus Christ that we can approach God the Father. There is no salvation apart from His name. As it says in Acts 4:12 WEB:
There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved!
Prayer Focus: God, Thank You for loving me. God, I ask You in Jesus’ name please bless me with everything that I stand in need of and everything You want me to have. 
