We truly empathize with your situation, Valfyl, and we're here to pray and counsel with you, leaning on the promises of God.
Firstly, we want to commend you for reaching out and acknowledging the power of prayer in Jesus' name. It's important to remember that it's only through Jesus Christ that we have access to God, as it's written: "For there is one God, and one mediator between God and men, the man Christ Jesus" (1 Timothy 2:5 WEB).
Let's pray for Dennis:
*Dear Heavenly Father, we come before you in the name of Jesus Christ to lift up Dennis. Lord, even though Dennis is in jail, we know that his physical circumstances don't limit Your love and power. We pray that You would be close to him, and that Your angels would surround and protect him. Lord, we pray that Dennis would turn to You in this time, seeking Your face and Your will for his life. We claim the promise that "you will seek me and find me when you search for me with all your heart" (Jeremiah 29:13 WEB). We pray that You would give Dennis a heart that seeks You, and that this time would be used for Your glory and his good. We also pray for those who are caring for Dennis, that You would give them wisdom and strength. In Jesus' name, we pray. Amen.*
As for your feelings of guilt, remember that each person is responsible for their own actions. While you can influence others, the choices they make are ultimately their own. Proverbs 16:9 WEB tells us, "A man's heart plans his course, but Yahweh directs his steps." Instead of feeling guilty, channel your energy into praying for Dennis and being a positive influence when you can.
We also want to address your concern for your son. Let's pray for him:
*Dear Lord, we lift up Valfyl's son to You. We pray that You would watch over him and protect him. We pray that he would know Your love and care, even in difficult circumstances. We claim the promise that "Neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, nor any other created thing, will be able to separate us from the love of God, which is in Christ Jesus our Lord" (Romans 8:38-39 WEB). Please be with him, comfort him, and guide him. In Jesus' name, we pray. Amen.*
Continue to trust in God, Valfyl, and don't hesitate to cast all your anxieties on Him, because He cares for you (1 Peter 5:7 WEB).