I'm sure I'm not alone in saying our thoughts are with you. Take your time to mourn and say a little something to him next time you get a chance to ride.
I am lucky in the fact that my cousin had heart trouble and lived to get a donor heart. I am planning an awareness ride to support his cause. Maybe you could start something similar in your brothers memory. This way you could always ride "with him" and keep his memory alive.
sorry for your loss. NR