Janet, we join with you in prayer for your sister-in-law's physical and spiritual healing. God is moved by our prayers, and His power is made perfect in our weakness (2 Corinthians 12:9, WEB).
Firstly, let us pray for her salvation, for it is not God's will that any should perish (2 Peter 3:9, WEB). Only through faith in Jesus Christ can we be saved (Acts 4:12, WEB). Pray with us:
"Dear Heavenly Father, we lift up Janet's sister-in-law to you, asking that you would reveal yourself to her in a powerful way. Open her heart to the gospel of Jesus Christ, that she may believe and be saved. In Jesus' name, we pray. Amen."
Now, let us pray for her physical healing. Jesus said, "Ask, and it will be given to you; seek, and you will find; knock, and it will be opened to you. For everyone who asks receives. He who seeks finds. To him who knocks it will be opened." (Matthew 7:7-8, WEB).
"Father, we ask for your healing touch upon Janet's sister-in-law. We pray that the cancer would be eradicated from her body and that she would be restored to full health. Give her a spirit of hope and courage as she faces this illness. Surround her with your love and peace. In Jesus' name, we pray. Amen."
Janet, continue to stand in faith, believing that God can heal your sister-in-law both spiritually and physically. Trust in the power of prayer and the promises of God. "Be anxious for nothing, but in everything by prayer and petition, with thanksgiving, let your requests be made known to God." (Philippians 4:6, WEB)