Well I can’t lie that it hasn’t been on my mind!
This is definitely a series based on Supernatural, and canon often plays a huge part in story twists. Though neither brother has died in any of the stories yet, don’t discount the possibility. In any AU.
As to this happening in BA, it actually was supposed to occur already, in my original storyline. This plot got scrapped during my falling out with my old editor, and the revamped story is what you see today. Because of that, I did actually have just ONE LINE that I jotted down back in the day.
I’ll leave you with that! (This line is in no way BA canon, and most likely will never be seen in the stories as they are).
“He wasn’t supposed to die before us…” Sam mumbled to the Impala. “We weren’t supposed to lose him.” He curled his legs close to his body, wrapping his arms around his knees.