I rather sympathized with little George, a basically good, polite, and obedient boy who does his best to please his fickle and ill-tempered granny, to no avail. If I could get away with dosing my nearest but no dearest with a dollop of George's Marvelous Medicine -- well, I better take the Fifth on that topic.
My attitude probably will not reassure adults who fret that undiscerning young readers may be inspired to emulate George's Graham Young ways, but this book is so crazy that I wouldn't be inclined to worry that children would take it as a life lesson. Unless you think your kid wants you dead; in that case, yeah, I wouldn't give him or her this book. You should maybe also not leave your 8-year-old home alone to cook for and medicate invalids, except in case of emergency (note: shopping does not qualify as an emergency).
But all's well that ends well, I guess. Unless you're Granny.