Brooks was a resident of the town of Blackwater in 1899.
Events of Red Dead Redemption 2
Arthur Morgan firsts encounters Jimmy Brooks in Valentine while assisting the gang. Brooks recognizes Morgan as having been in Blackwater, and after Morgan unsuccessfully attempts to convince him otherwise, Brooks rides off in fear. Morgan chases him across the country on his horse until Brooks falls off his own and is left hanging off a cliff, and then Morgan has the choice of either helping him, or letting him die. If rescued, Morgan threatens Brooks into not talking, who then proceeds to ride off. Brooks's final words to Arthur can be one of the lines he reflects upon during his last ride.