Hugs, Anna. I read "kids, parents, power struggles" recently and it seems to help a lot with this kind of situation. It suggests to name his emotions or how you think he's feeling... For instance, this evening we were in the car on the way home just after lots of snacks and it's 6:40, our normal bt is around 9 these days. DS started getting very whiny and complained and cried that he had pain but couldn't tell me where it was. I thought it was the diaper being too tight, I loosened it. He kept whining and like this annoying cries. I was almost to a point of ignoring him because he's not helping me to help him. I suddenly remember the book and just asked him if he's tired, because he just yawned and then I realized he might actually be hungry, I asked if he was hungry and if he wanted a sandwich which i had prepared for lunch. He immediately went quiet, nodded, and took the sandwich and was happily eating.
The book says that no child is out to get us, when they behave in this way to disagree with us or not listening to us, it's fueled by a reason. If we help find the reason by talking or by naming it, it would lower the intensity and can help finding a solution, sometimes it's just about being understood.
I am not sure what emotions or reasons Stan might have at the time, can it be just tired? Too tired to chew on proper food or he just wanted something cold and easy to eat? Do you think you know why he got like that this evening?