I'm still struggling with conveying, "you have to get the stainless pan hot and lay down some fat before you add the food, or it will stick".
Would she be willing to use a timer? She can just set it for 10 - 15 minutes after turning the burner on, and avoid putting anything in the pan until after the timer is done.
I've certainly ruined my fair share of eggs by rushing, but having the patience to let it get up to temperature is pretty much the only "hard" part of using cast iron.