I cured this drug addict NPC and started to trade with him. I noticed that it doesn't refill his trades, even after leveling. There seems to be no POI block for it in the source code. So I waited the next day and still no refill.
Sollace commented
Eeyup. That's a major minor oversight.
The drug addict villager is in general a bit half-baked, no pun intended.