I never expected anything too highly from this series, but I gotta say him being able to cast spells like that even if it requires other people's MP is a shame. They tout him as being OP specifically because of inspect, which is cool, because it is very strong, and usually treated as a tack on in series, and yet, here he is being conventionally OP.
In my opinion the series could've benefited from either not having this encounter, or them dying in the end. Better yet, for him to have specifically learned a specific obscure recipe for cure instead of being able to cast super healing. That would've fit the story more, if there was a cure for that poison that used a certain combination of ingredients one might expect.
Still, the series is a time killer and stuff regardless, but it does feel a bit squandered in things like this.
Oh great, slavery added in too? That squanders it a thousand times more than OP slot devices. Why in the fuck are so many manga obsessed with that awful trope. Not to mention cat lady specifically lamented how something like healing could be used for enforcing slavery directly before suggesting it. WHY? That makes no sense.