I'm going to tell my brother that his birth defect hasn't affected his life in the same way that my stroke has affected my life
Why would you say that to your brother?
These days people love open confessions.
You are behaving insensitively towards your brother regarding his birth defect. Even though it might not be as bad as what you have dealt with, your brother still has to cope with his birth defect every day. You should be able to understand his ordeal, and at least feel some sympathy for him.
Oh shut up. It's never bad to help others.
I understand that you want your brother to hear this, because you believe it will help him to keep things in perspective, and your goal is noble. However, saying it to him like this will just cause unnecessary hurt feelings. Tell him that you understand how he feels, but you want him to do the same for you.