What to say...
I don't know, what is the proper noise to make?
I'll say what is in my heart then: SirGod, the pain you are feeling is something that no body can even begin to understate unless they lost a child--and the only thing that does is demonstrate that each one's loss is unique and painful in it's own way. So no one can relate to the pain you and your sister are feeling.
This does not mean that you are alone, however. Don't be afraid to reach out to your family and your friends here on this fourm, and don't be afraid to stay alone when you need to. This pain won't go away, just as your love of him would not go away, but you will move on nonetheless.
This news has caught me off-guard, as it always does. I can only say this: Celebrate his life. It might have been short, but it was obviously around good people and loving parents, and he obviously gave you much love.
Don't forget that.
I'll light a candle for you tonight SirGod