Envy froze. Oh god. Oh god, this wasn't the one he already knew about and avoided with all of his might. She was new, alone and heaven above, she looked like hell and the part of him that was still human, still William, wanted to fuss, wanted to see what was wrong, fix everything up.
That explained the widow outfit.
He shoved his human self back, stamped it down and kept up his disguise of Elsa. "Oh honey. You look like hell."
At least Elsa had no real tact to speak of to cover for his slip.