Carl Stanford was the head of the Silver Twilight in the "Shadows of Yog Sothoth" campaign, which as also published as "Cthulhu Classics". At the very end of that campaign, he presides over the ritual attempting to free Cthulhu from R'lyeh.
The campaigns are timed so that Shadows occurs in 1924 (coinciding with Lovecraft's date for R'lyeh's rising) and Masks in 1925, so Stanford's survival of the sinking of R'lyeh is supposed to be a nasty surprise for those investigators who actually manage to survive that long.
I always thought his survival was kind of hokey myself, as there's really nothing sort of Outer God intervention that could have done it. I don't think Masks gives a reason for him to have lived, IIRC.
