We understand that you're going through a struggle of faith. You mentioned that Jesus could not answer a simple prayer, and this has led you to consider no longer believing in Him. First, let's address the idea that Jesus couldn't answer your prayer. In the Bible, it says, "Again I say to you, that if two of you will agree on earth concerning anything that they will ask, it will be done for them by my Father who is in heaven. For where two or three are gathered together in my name, there I am in the middle of them." Matthew 18:19-20 WEB.
Jesus wants to answer our prayers, but there could be several reasons why it might feel like He hasn't. Sometimes, it's because we ask with the wrong motives or our requests do not align with God's perfect will. We are only asking for personal desires and not for God's will and blessing. "You ask, and don't receive, because you ask with wrong motives, so that you may spend it for your pleasures." James 4:3 WEB.
Other times, it might be because we need to persist in prayer and wait on God's timing. Jesus Himself teaches us the importance of persistent prayer in the parable of the widow and the unjust judge in Luke 18:1-8.
Regarding your statement about no longer believing in Jesus, let us remind you of His love and sacrifice. Jesus came to earth to save us from our sins and reconcile us to God. "For God so loved the world, that he gave his only begotten Son, that whoever believes in him should not perish, but have eternal life." John 3:16 WEB.
It is only in the name of Jesus that we can come to the Father. "Jesus said to him, I am the way, the truth, and the life. No one comes to the Father except through me." John 14:6 WEB.
Let's pray together:
Dear Heavenly Father,
We come before You in the name of Jesus, lifting up our brother who is struggling with his faith. Lord, we ask that You reveal Yourself to him in a powerful way and help him to understand that You are always working for his good, even when answers to prayers seem delayed or unanswered. Help him to trust in Your timing and Your will, and to persist in prayer. Remind him of the love and sacrifice of Jesus on the cross, and draw him closer to You. In Jesus' name, we pray. Amen.
Remember, it is only in the name of Jesus that we can come to the Father. Hold onto your faith, and keep seeking God with all your heart. He promises that you will find Him when you seek Him in this way. "But seek first God's Kingdom, and his righteousness; and all these things will be given to you as well." Matthew 6:33 WEB.