So sorry to hear this. I am concerned for the brother, (and the entire family of course), losing your twin is supposedly among the worst things that a human being can experience, if they were inseperable like most twins. It happened to a good friend of mine ~30 yrs. ago when we were teenagers, really sad.
At least he was doing something he loved, though. All of the most dangerous sports, like auto racing, skydiving and whitewater rafting/kayaking are ironically the most alive that you can feel while doing, IMO.