see the problem with "it should have been Percy who died" fix it fics is that the Weasleys are almost never as messed up over it as they are when Fred dies if they show any reaction at all
Which like I know why. The only people who write that either don't like Percy or consider him irrelevant so in their perspective the Weasley family was not broken and they didn't really lose anyone
but it's still just so damn boring life just goes on like nothing really happened with only really maybe Molly having any sort of reaction to it
If you're going to kill him let it mess them up let them grieve him let Arthur blame himself over losing their last few years with him Let Fred be the one torn up over watching his brother die and feeling like it's his fault