BloodyMary AU where Simon wakes up on the Hail Mary rationalizing that Grace is an angel and never un-rationalizes it.
His stressed to the max, death cult-programmed, probably mutated brain just straight up refuses to ever acknowledge the fact that Grace is just as human as he is was, and like, imprints on the guy like a traumatized duckling with too many teeth.
Grace does something wondrous/scientific = Must Be An Angel ¯\_(ツ)_/¯
Grace does something mundane/dumb = Still 100% Angel, He Has To Be
Grace, for his part, tries SO HARD to get his new friend to stop revering him so fervently, but eventually realizes that, although he may have a doctorate, it’s not in psychology.
Allowing Simon to treat him as a warped-ass, Eden-approved version of an angel was in fact not hurting Simon’s mental health, but probably actually preventing his mind from splintering entirely.
Was allowing his newest roommate to delude himself into thinking Grace was a holy being rational, safe, sane or moral?
Probably not? But it’s worked out fine so far!
Simon, on his end, knows that he’s a sinner, a blasphemer, a Butcher. He knows that worshiping an angel in general is sacrilege, and that desiring and coveting one was even worse.
But with Grace, his Grace, he allows himself to sin in shame. To kneel at his saviors feet and be touched so tenderly by an angel’s all-accepting mercy.
And, of course, over in the corner, Rocky remains just as confused by the mutated human as Grace initially was.