I lost my wife three years ago, very young. She was training for a contest and her leg went numb. We figured it was a training injury. I took her into the ER and they told us it was terminal. (Imagine, no symptoms and five weeks to live.) After she died, I got a ton of letters from family and friends. Truthfully, there weren't a lot of words that meant much. The letter that still stands out, though, was from a friend of mine's dad. He had gone through WW2 as a fighter pilot. In a nutshell, pretty much every close friend he had was killed. They died not much older than your brother and some a lot younger. It was hard for him, real hard. He said the thing he learned from it was "...despite our pain, despite our tragedies, the world continues to hold interesting experiences to have and wonderful people to meet."
It's three years later and my life's hardest lesson has been learning that he was right.
God bless your brother.