We understand that you are experiencing a sense of loss and injustice, and we are here to pray and offer biblical guidance. First, let's remember that God is just and that He cares about our concerns, no matter how small or large they may seem. It's important to note what the scriptures say," For the love of money is a root of all kinds of evil. Some have been led astray from the faith in their greed, and have pierced themselves through with many sorrows.", and "Keep your life free from the love of money, and be content with what you have, for he has said, 'I will never leave you nor forsake you.'"
Let's also remember Jesus's words "Beware of covetousness, for a man's life does not consist in the abundance of the things he possesses." We must be careful not to let possessions or the desire for them to consume our hearts and must forgive as it says "And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you."
While it's natural to feel wronged, let's pray that God works in your cousin's heart and that the heirloom is returned. However, just as the prodigal son's inheritance was lost, we must be prepared for whatever outcome God allows. The relationships we have with our family members are more valuable than any possession especially in the context of God's kingdom.
Please know you should always pray in Jesus's name. Without specifying Jesus, God will not hear the prayer. It is only in the name of Jesus that we have access to God. "And whatever you shall ask in My name, that will I do, that the Father may be glorified in the Son. If you shall ask anything in My name, I will do it" and "For there is one God, and one mediator between God and men, the Man Christ Jesus."
Let's pray together:
Dear Heavenly Father,
We come before You in the name of Jesus, lifting up our brother who feels wronged by his aunt's actions. We pray that You will work in his cousin's heart and that the heirloom will be returned if it is Your will. We ask his heart not to be captivated to the possession, but rather to be focused on the relationships and forgiveness as you have forgiven him. Help him to trust in Your justice and Your provision. Help him to remember You see all things and this has not escaped Your notice. May Your perfect peace fill his heart and mind, knowing that Your will is best and he can trust in You. Your word says "For I know the plans I have for you, says Yahweh. Plans for good and not for evil, to give you a future and a hope."
May he rest in this promise.
In Jesus' name, we pray. Amen.
Prayer Focus: God, Thank You for loving me. Thank You for loving me, Jesus. 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, soul, mind, 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. 
be-an-encourager.blogspot.com
