With a high enough Speech skill Jeb will tell the player that he is also a chem dealer, and the Prisoner will then be able to buy chems after midnight. One of Jeb's more exotic compounds is a modified concentration of Sym, which he reveals is irradiated dog saliva that has the same effect of 4 doses of jet.
Jeb has not appeared nor is he mentioned in any published game. He was to appear only in Van Buren, the canceled Fallout 3 by Black Isle Studios. It is not certain if he will appear in any future Fallout game.