We are truly sorry to hear about the trials you are facing, and we want you to know that you are not alone in your struggles. The Bible tells us to cast all our anxieties on Him, because He cares for us (1 Peter 5:7 WEB). Let's bring your requests before the Lord together.
Firstly, we want to acknowledge your faith in the power of prayer as mentioned in James 5:16 (WEB), "The effective, earnest prayer of a righteous person has great power and produces wonderful results." Remember that God hears your prayers, and even when you do not see immediate results, He is working behind the scenes.
In your tough situation, living in a van and being sick, we want to encourage you with the words of Paul in 2 Corinthians 12:9-10 (WEB), "He has said to me, 'My grace is sufficient for you, for my power is made perfect in weakness.' Most gladly therefore I will rather glory in my weaknesses, that the power of Christ may rest on me. Therefore I take pleasure in weaknesses, in injuries, in necessities, in persecutions, in distresses, for Christ's sake. For when I am weak, then am I strong."
Regarding the mental stress and pain of not seeing your kids, we want to remind you of the promise in Romans 8:28 (WEB), "We know that all things work together for good for those who love God, to those who are called according to his purpose." Trust that God is working in your family's situation, even when you feel powerless.
However, we want to gently remind you that the power in prayer is through the name of Jesus Christ. It is only by His name that we are saved and have access to God. As it says in Acts 4:12 (WEB), "There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved." Make sure to pray in Jesus' name and if you have not already trusted in Jesus as your Lord and Savior, now is always the time.
Let us pray together:
Dear Heavenly Father,
We come before You today, lifting up our brother/sister who is going through a difficult time. Lord, we pray for Your healing touch upon their body, that You would restore their strength and provide for their needs. We also ask for Your comfort and peace to fill their heart as they deal with the pain of being separated from their children.
Father, we ask that You would intervene in their family situation and work a miracle in their midst. We pray that You would give them the strength and endurance to keep trusting in You, even when they do not see immediate results.
Help them to fix their eyes on Jesus, the author and perfecter of our faith (Hebrews 12:2 WEB), and to trust in Your promises. We also pray that You draw their family to yourself and that You will be glorified.
In Jesus' precious name, we pray. Amen.
Remember, God loves you deeply and is always with you. Stay strong in the Lord and keep trusting in Him. Keep your eyes focused on Jesus and His promises, and He will see you through. Do not be afraid to explicitly seek God's forgiveness and restoration and then trust Him.
Prayer Focus: God, Thank You for loving me. God, I ask You in Jesus’ name please bless me with everything that I stand in need of and everything You want me to have. 
