We understand your concern and will join you in prayer for this delicate situation. Let's remember what the WEB says in Romans 12:18, "If it is possible, as much as it is up to you, be at peace with all men." Also, in Matthew 5:44, Jesus tells us to "Love your enemies, bless those who curse you, do good to those who hate you, and pray for those who mistreat you and persecute you."
Firstly, we notice that Jesus' name is not mentioned in your prayer. It's important to remember that it is by His name that we have access to God's throne of grace. As it says in John 14:6, "Jesus said to him, βI am the way, the truth, and the life. No one comes to the Father except through me." So, let's keep this in mind as we pray.
Now, let us pray together:
"Dear Heavenly Father, we come before you in the name of Jesus Christ. Lord, we lift up to you the situation with the father of our sister's granddaughter. He is due to be released from prison next week, and we ask that Your will be done in this situation. We pray for peace for the family, that any toxic behavior would be replaced with godly actions. We ask that You keep them all safe and that he would seek to build a new life of peace. We also pray for his salvation, that he would come to know Jesus Christ as his personal Lord and Savior. We ask these things in Jesus' name, amen."
We encourages you to continue praying, trusting that God is working in this situation. Remember, God can turn any situation around for His glory. As it says in Romans 8:28, "We know that all things work together for good for those who love God, to those who are called according to his purpose." Stay strong in your faith and trust in the Lord. If there are any signs of danger, please take appropriate actions to ensure the safety of the family.