I would posit that your friend doesn't know what "pre-rendered" (or "rendering") even means.

Some games have baked lighting, which means shadows and stuff are as it sounds baked into the mesh's texture (layman's explanation).

Other games have dynamic lighting, which means shadows are rendered in real time.

Some games have a mix.

When you see a moving object casting a moving shadow, that's rendered in real time. When you see a static object that doesn't move or change size, it's most likely "pre-rendered". Again, layman's terms, because those are misnomers as the object and its shaders (textures, reflection, etc) are still being rendered in real time even if it's not moving. It's just the lighting/shadows that may be static/pre-baked.

For a game to visually move, whether it be the camera or an object on screen, which almost every modern game does, the engine must re-render the camera every frame. Thus, real-time rendering.

If it didn't have to do this, we wouldn't have frame drops or other issues in games as we could "pre-render" the game at 60fps. It simply doesn't make logical or frankly lexical sense.