Well, with the word "can" the sentence basically means "he could stand up any moment now and turn the world upside down", whereas using "could" would make it look like a possibility "yes, if he was to try, he could in fact turn the world upside down".
But I don't think it's wrong to use the word "can"?.. It conveys a different feeling compared to "could". "Can" makes it feel more in the now. If that's the effect you're going for, I think it's perfectly correct.