My 3 yo son goes through that periodically, his twin sister eats anything that doesn't eat her first.
I spoke with a nutritionist when he was younger as I was worried as my kids tend to be small to begin with (3 yo's are barely over 25 lbs! and still wear 2T), they said not to worry as they will eventially get the nutrion their body needs over the course of a week, just to continue making things and offering because eventuall they will take it. As for my kids if they skimp on breakfast foods, I try to offer more snack through the morning..
Maybe and hour later i will offer some fruit, then a bit after that something with peanut butter or other protein they might find interesting, but in smaller snack size amounts. etc. If they don't eat all of their snack I don't worry about it too much as it will mean they will still be hungry at lunch time.
I hope this helps. I would take the mom up on her offer for the oatmeal recipe...Sometimes doing things like that will be your only way to get a larger variety into your kid's diet (i.e. my son refuses to eat most vegetables - though, thanks to blue's clues he now eats carrots - so i sneak a couple of vegetable servings in by offereing him the new V8 juice options that are mixed with fruit juice and you can't taste the veggies! 1 glass is 1 serving of fruits and 1 serving of veggies!)
Good Luck!!! ;-)