not sure what the man could do sitting there on the off end of the carriage unless he is conveying instructions to the operator.
those old big lathes could turn things so massive that it took 2 guys to run them 1 to watch what was going on and the other to run the controls.
I suspect for some things that big n of mine would be the same way, needing someone to watch the tool as it became close to the end of a counter bore so it can be kicked out of feed then hand fed the rest of the way, and also to relay the chip conditions
I noticed he also has a drop light or the lathe light positioned to peer down the bore