Looking at the picture, I expect the guy closest to the camera on the analogue console is actually mixing FOH and the guy on the digital mixer in the background (clearly wearing in-ear monitors) is mixing monitors.
You can't really mix monitors on a big analogue desk very easily, they're not set up for the number of output channels (sends) you need. Usually every main performer of a band has their own separate stereo mix.
During the show, for FOH it's usually just riding faders (adjusting volume of each channel) and making little effect/EQ changes if something sounds off, most of that stuff should be pretty well set up beforehand.
You can't really mix monitors on a big analogue desk very easily, they're not set up for the number of output channels (sends) you need. Usually every main performer of a band has their own separate stereo mix.
During the show, for FOH it's usually just riding faders (adjusting volume of each channel) and making little effect/EQ changes if something sounds off, most of that stuff should be pretty well set up beforehand.