I think that it is well known that nut allergies can be deadly. The waitress should have checked with the kitchen staff to see if there were nuts in the cake when Andy asked.
I think that the waitress screwed up. This one little mistake could have cost lifesaver his life and not just $450. I think that the restaurant should compensate lifesaver for the cost of his ER visit. I also think that restaurants ought to better train their wait staff. If a customer asks about the ingredients in the foods on the menu, the restaurant through the waitress has a responsibility to give an accurate answer. Restaurants have a responsibility to provide a list of ingredients in their food that can cause allergies like nuts. Putting detailed ingredient lists on the menus like packaged foods is a good idea.
Lifesaver, I hope that you're feeling better, sweetie.