Like all other roaming NPCs, Withering Lottomen roam freely throughout the Nether, and can only despawn once 40 minutes pass after first spawning. Their despawn can be prevented by naming them using a name tag.
Withering Lottoman uses trading mechanics similar to vanilla Minecrafttrading.
The Nether member of the lottomen group, withering lottomen are the only lottomen besides the overworld members they do not reside in some sort of structure. The distinctions end there however, as they are just as unwilling to discussion anything except trade as any other lottoman.