HIGH IQ strategies to dealing with Isobel stupidity

When I played with my girlfriend, she kinda had a really good idea to deal with her dumbness. We straight up used hold person on her (im not sure it was this spell, but what I remember is that we paralyzed her somehow) and then threw an invisibility potion to her. She took no damage till the end of the fight. Note: in my first playthrough I actually let her die cuz I wasnt expecting the dumbness, so I warned my gf that it would be tricky. What where your High IQ strategies? 😅