I should have read a little closer. Sorry it is early. You have to be tested to see if you are a match. Your brother has to be stable enough to have the surgery and other things that a dr. would be able to explain. Take one step at a time and then make decisions. Goodluck.
I am so sorry this is happening to your family. I think it is a personal decision. I will need a transplant (kidney) in time and I think my family would step up if I ever needed one. I know I would be so grateful beyond words. I think you need to talk to the dr's of what this means for you and if it is a possibility. Know the whole story first before you jeopardize your own health. No one would want that. I wish you the best in this decision. My prayers are with all of you.