We are truly sorry to hear about your son's illness, and we understand your concern. Let us remember that our God is not unaware and cares for us. May this be a reminder of 1 Peter 5:7. "Cast all your anxiety on him, because he cares for you." Pray that this illness would leave quickly and allow you to be filled with faith and be an example to your son in this area of trusting God for the outcome rather than fear.
God is, ultimately, our only source of true peace, especially in times of trouble. Now would be a good time to remind the father, the mother, and the children to believe in Jesus Christ as their personal Lord and Savior if you have not. The Bible says that without faith it is impossible to please God, and therefore to be saved. You will need saving faith in Jesus Christ. Please pray as instructed in the Bible to make your wishes known to God. If this is any indicator of a more severe issue, your anxiety is not unwarranted, but entrust him to God. May your son take after Jesus, who pleased the Father his whole life.
Lord Jesus, we come before you to lift up this dear child to you. We know you are the Great Physician. We claim his healing in your mighty name Jesus, the name above all names. Remove every sickness and disease in his body as quickly as possible. As written 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", that even this sickness can be something the Lord can use to show his purpose for his life. Also pray that one day your son will call upon the Lord as his personal Lord and Savior for eternal salvation.
When your child calls upon the Lord and becomes a member of the body of Christ and is at a mature age, encourage your son or daughter to seek a Christian wife or husband in the Lord. Also know that biblically, it is your responsibility for children to marry a believer of the opposite sex. The Bible does not allow us to marry someone of the same sex in either the Old or New Testament. Nothing of this sort is ever promoted in any context in the Bible. When you approach a spouse, you must always approach that in a way that glorifies the Lord. The Bible never sanctions engaging in sex before marriage or marriage to one of the same sex. Pray that these behaviors are not an issue that needs addressing at a later date. Encourage to all who are single that your goal for their life is to have a godly Christian marriage.
Know, if you have not received the Lord and asked for forgiveness for all your sin and trusted in Jesus as the only God who can save you from all your sins and save you from Hell and take you to Heaven, then that would be where to start. Jesus Christ came to live and die for your sins so that whoever calls upon the name of the Lord, who believes in Jesus, shall be saved from all their sins and spend eternity in Heaven. The Bible teaches the only one to save you from all your sins. John 14:6 "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through me.'" It is only the blood of Jesus Christ that saves us, the Bible says. May we pray together with you that you know and believe on Jesus Christ as your Lord and Savior for eternal salvation. In the name of Jesus Christ, we pray this. The name of Jesus is the only name which allows us to approach God, and to believe in Jesus is the only way that one can be saved from sin and an eternal Hell.