Will pray without ceasing...
I'm so sorry to hear about your brother. I know that this must be heartbreaking for both of you. One thing I wanted to ask right away is if he's on the list for a kidney transplant and whether or not there is a registry where people can get tested to see if they're a match? I'm sure that many here would be willing to go and see if we matched and that there are others in your area who would be willing to do the same. I have a friend who did have a kidney transplant and it really helped her-she does not live in pain all the time now.
I will certainly be praying that God would be with your brother and would ease his pain so that he might live a fulfilling life with whatever time he has-long or short-on this earth. Has he tried any alternative medicines or therapies, such as herbal supplements and/or holistic therapies like meditation/fresh air? I wonder if these might be helpful as ways to mangage pain through a change in environment/a channelling/control of one's pain/stress.
I also have some good prayers somewhere that deal with praying for oneself or another person against sickness and pain. I will try to find them and send them to you via pm. I empathize with your brother just wanting to go home to heaven-that is the Christian hope, after all, and the place where God will be with us without any pain or sickness. We will be made whole. However, I pray that if it is God's will, he will open avenues to enable your brother to survive as a physically healthy person. And, as Jesus said of the blind man he healed in John 9, sickness and disability can be used to further God's glorty-so, remind your brother of how precious he is to God and of the inspiration he is to you. And, just simply be there to be empathetic. Please let us know if we can be of any further help or if any of us can help by getting tested as a possible match or encouraging others to do so.