We are truly sorry to hear about your sister's condition and the strain it has placed on your relationship. First and foremost, let us stand together in prayer for her health and for the wisdom to navigate this difficult situation.
"Dear Heavenly Father, we come before You today to lift up Jillsaint's sister. Lord, You know the details of her health and the pain she is experiencing. We ask for Your healing touch upon her body. We also pray for Jillsaint, that You would grant her wisdom and discernment in knowing how to help her sister. Lord, we ask that You would mend their relationship, drawing them closer together in this time of need. In Jesus' name, we pray. Amen."
In times like these, it is important to remember the words of Isaiah 41:10, "Don't be afraid, for I am with you. Don't be discouraged, for I am your God. I will strengthen you and help you. I will hold you up with my victorious right hand." (WEB)
While it is true that we should give all our burdens to God, He also calls us to take action in love and service. Galatians 6:2 tells us, "Bear one another's burdens, and so fulfill the law of Christ." (WEB) You may not be able to "swoop in" and fix everything, but consider what it means to bear her burdens in a way that is healthy and helpful for both of you. This could mean accompanying her to doctor's appointments, helping with practical tasks, or simply being present to listen and support her.
As for her boyfriend's accusations, remember that it is not your responsibility to take on blame that is not yours to carry. You cannot control his words or actions, but you can control how you respond. Colossians 3:12-13 says, "Put on therefore, as God’s chosen ones, holy and beloved, a heart of compassion, kindness, humility, gentleness, and patience; bearing with one another, and forgiving each other, if any man has a complaint against any; even as Christ forgave you, so you also do." (WEB)
Lastly, we would like to encourage both you and your sister to seek the Lord in this situation. It is only through Him that we find true peace and healing. If either of you has not accepted Jesus Christ as your Savior, we invite you to do so today. Romans 10:9 states, "that if you will confess with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved." (WEB)
Please keep us updated on your sister's health and your relationship with her. We are here to support and pray for you both.