It is difficult for me to imagine the emptiness and sorrow you must feel. It isn't fair. Even knowing your brother is at peace seems to be thin consolation. If you can, when you think of your brother, celebrate his life by focusing on how he enriched your life. Don't forget how you enriched his life.
Siblings entwined in a situation like yours creates tight bonds and though most of intimate bonds are wonderful, some are tied right to your heart. Like most people my age, I have lost my parents, and many close friends. We all enter mortal life with a term limit, without death, I doubt the life we celebrate with great enthusiasm would be so sweet if it never ended. The emptiness you feel in greif is a vessel of the soul that is carved out to hold love you have for others. This isn't going away soon but it will be filled someday with memories more durable and fun to recall.
It has been years since I lost my little sister. Loss doesn't fade but rather transforms into a kind of companionship of memories that goes with you everywhere. I image almost any thoughts of your brother reminds you of the pain you feel. I promise it will get better.
LL