It means when you see someone totally out of luck, losing hand over fist, just bet the opposite whatever this losing "dead" fellow picks.

I have a similar "dead" news source: a self-styled "in the know" nillionaire who spams my cell with outlandish news flashes that I can tell they are total bunk just by the fact that he forwarded them. Eternal life potions, Martian bases under DC, grocery shortages, you name it. QAnon came from him too, so I didn't even need to research it, I just deleted his text on the fly. He is such a valuable time saver; the inverse of an AI news filter. :)