The actual screenshots only show like 10k lines of code from the procedural generation system and custom render tech. Its a fully playable RPG game, the lines are split on quest systems, stat stuff, inventory, ui, dungeon generation, enemies, etc.

The world is being generated at startup for a 50-50 kilometer play area through multiple steps of generation that includes city placement, roads, and various biomes.

Has 3 months of dev time right now

that's reasonable I think if he isn't using any kind of game framework.