Or, ya know, he just does whatever it is because we are talking about MOTHER WINTER, a literal force if nature and an elderly woman to boot. Harry respect women. Harry respects his elders. Harry lips off to gods, but still plays nice if they're not trying to kill him. I can see her telling him to commit this unspeakable atrocity like she's telling the neighbor boy to mow her lawn, and Harry trying desperately to find a way to do it without sacrificing a litter of puppies. Scary, yet hilarious.