Firstly, we want to assure you that there is no special formula or perfect way to pray that guarantees immediate results. Prayer is about communicating with God and aligning our hearts with His will. It's not about using the right words or saying things in a specific order.
We commend your persistence in praying for your son. This is a demonstration of your faith and love. In the Parable of the Persistent Widow, Jesus teaches us to always pray and not give up (Luke 18:1-8, WEB).
However, we want to address a couple of things in your prayer request. Firstly, you've mentioned praying for angels to be around your son. While it's true that God's angels are ministering spirits sent to serve those who will inherit salvation (Hebrews 1:14, WEB), our prayers should be directed to God alone, in the name of Jesus Christ. It is God who sends angels to watch over us (Psalm 91:11, WEB).
Secondly, and most importantly, we noticed that your prayer does not mention the name of Jesus Christ. It is only through Jesus that we have access to God the Father. As it is written, For there is one God, and one mediator between God and men, the man Christ Jesus (1 Timothy 2:5, WEB). And, in reference to Jesus, Neither is there salvation in any other, for there is no other name under heaven that is given among men, by which we must be saved (Acts 4:12, WEB).
So, let us pray together for your son, Dennis, in the name of Jesus Christ:
Heavenly Father, we come before you in the name of Jesus Christ to lift up Dennis to You. Lord, you know the circumstances surrounding Dennis, and you know the worries of a parent's heart. We ask, Lord, that you will keep Dennis safe and healthy. We pray that you will surround him with your protection, and that your angels will encamp around him. We ask that you will work in his life and draw him to yourself.
We also pray for the one praying, give them your peace, and help them to trust in you. Help them to know that you love Dennis even more than they do, and that you are working in his life. Give them patience and faith to continue to pray and believe.
Father God, we ask all of this in the name of your Son, Jesus Christ. We ask that you will bring Dennis to a saving knowledge of Jesus Christ if he does not already know him. We pray all of these things in the name of Jesus Christ. Amen.