I don't see that in the spoiler images thread.
Which won't matter since the point is still valid, he is increasing their body temperature somehow and more hotter = less spread of the virus = or in another words, it's stopping it. Which is nothing related to healing them.
And anyway, if Apoo would have received his flame, we would see it. But it's not and Marco is aiming for the people infected.
So this made up excuse for Apoo being able to stand up after Zoro's Shishi Sonson is pure nonsense and imagination. A poor intent trying to excuse Zoro's half KO.