We understand the urgency and stress you're feeling in your current situation. Firstly, it's important to remember that God is our provider and that we should trust in Him in all circumstances. As it says in Matthew 6:25-34 WEB:
"Therefore I tell you, don’t be anxious for your life: what you will eat, or what you will drink; nor yet for your body, what you will wear. Isn’t life more than food, and the body more than clothing? See the birds of the sky, that they don’t sow, neither do they reap, nor gather into barns. Your heavenly Father feeds them. Aren’t you of much more value than they? "Which of you, by being anxious, can add one moment to his lifespan? Why are you anxious about clothing? Consider the lilies of the field, how they grow. They don’t toil, neither do they spin, yet I tell you that even Solomon in all his glory was not dressed like one of these. But if God so clothes the grass of the field, which today exists, and tomorrow is thrown into the oven, won’t he much more clothe you, you of little faith? "Therefore don’t be anxious, saying, ‘What will we eat?’, ‘What will we drink?’ or, ‘With what will we be clothed?’ For the Gentiles seek after all these things, for your heavenly Father knows that you need all these things. But seek first God’s Kingdom, and his righteousness; and all these things will be given to you as well. Therefore don’t be anxious for tomorrow, for tomorrow will be anxious for itself. Each day’s own evil is sufficient."
It's clear that you are in a difficult financial situation, but we must also address that turning to family for support should not be met with ultimatums. It's important to foster love and understanding in families, as instructed in Colossians 3:14 WEB:
"Above all these things, walk in love, which is the bond of perfection."
As for your desire to sell something of value, we encourage you to pray for God's wisdom and guidance. Proverbs 3:5-6 WEB says:
"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."
Let's pray together:
"Dear Heavenly Father, we come before You today to lift up our brother/sister in need. We ask for Your divine provision and guidance in their life. Help them to trust in You and Your timing. Open the right doors for them to sell their valuable item, and give them the wisdom to discern the right path. Soften their sister's heart and bring healing and understanding to their relationship. Help them to seek Your kingdom and Your righteousness first, knowing that You will provide all they need. We ask this all in Jesus' name. Amen."
Lastly, we want to gently remind you that it is only by the name of Jesus that we have access to God. Acts 4:12 WEB says:
"There is salvation in none other, for neither is there any other name under heaven, that is given among men, through which we must be saved!"
If you have not already, consider inviting Jesus into your life and trusting in Him for your salvation and daily needs. May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all. Amen.
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. 
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