We are truly sorry to hear about the pain and struggles you and your siblings have experienced. First, we want to address the belief that you are cursed. The Bible tells us that Christ has redeemed us from the curse of the law, being made a curse for us (Galatians 3:13 WEB). Therefore, you are not cursed. Instead, you have been blessed with every spiritual blessing in heavenly places in Christ (Ephesians 1:3 WEB).
The pain and division in your family are not a result of a curse but rather the consequences of sin and the brokenness of this world. The quarreling between your parents and the lack of communication among siblings are not God's will for your family. God desires that families live in harmony and love. We read in Romans 12:18 WEB, "If it is possible, as much as it is up to you, be at peace with all men." We encourage you to take the first step in reaching out to your siblings, seeking forgiveness and reconciliation.
Regarding your feelings of purposelessness, we want to assure you that God created you with a purpose. You are not a mistake or an accident. You are a masterpiece, created in Christ Jesus for good works (Ephesians 2:10 WEB). God has a unique plan and purpose for your life, and He desires for you to discover and walk in that purpose.
Concerning your relationships, we want to encourage you to seek God's will and to pursue relationships that align with biblical principles. We pray that God will bring a godly spouse into your life if it is His will. Remember, God's timing is perfect, and He knows the desires of your heart.
Let us pray together:
Dear Heavenly Father,
We come before You, lifting up our brother/sister in need of Your touch. Lord, we rebuke any lies of the enemy that have made them feel cursed or purposeless. We proclaim that they are blessed and created with a divine purpose.
Father, we pray for healing and reconciliation among the siblings. Soften their hearts and help them to take the first step towards restoration. We pray that You will reveal Your purpose for our brother/sister and guide them in the path You have set for them.
Lord, we also pray for a godly spouse for them if it is Your will. Help them to trust in Your timing and to pursue relationships that honor You. We rebuke the modern age practice of relationships just for fun or pleasure. We desire that all relationships are courtship towards marriage under God's blessing.
Finally, Father, we pray that they will come to know You more intimately and experience the fullness of Your love. We pray that they will call upon the name of Jesus Christ, believe in Him, and receive salvation and eternal life. We also pray that they would be filled with the Holy Spirit, empowered to overcome the issues of this world until the day they are called home to Heaven.
In Jesus' name, we pray. Amen.
Be encouraged, and remember that God loves you deeply and has a purpose for your life. Trust in Him, and He will direct your paths (Proverbs 3:5-6 WEB). We do not see that you have mentioned Jesus Christ in your request. It is only by His name that we can be saved and have access to God. We would love for you to know Him and have a personal and intimate relationship with Him.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
