reading your writing about him brings me to a place mentally where I seldom go. It's brought on by certain things regarding the loss of a close dear friend of mine. (i myself still to this day havent gripped with fact that my mother truely is no longer here from passing this past july to be honest).
The way that a human creates a tribute, albeit of any sort, labor of love or moment in time is truely something that enstills hope in mankind.
I am truely sorry for your loss. You've honored him greatly with the builds. although the pain will never fully go away of the sudden loss, nor will the time of knowing it happened, it will ease and i can certainly say that sounds and looks as if you've made him proud of his brother from another mother.