He could have just been thinking, like about a recipe or a menu. Don't be so quick to take it personally. Usually managers are told to smile because the workers under them will take it personally, but I think chefs are exempt from this - maybe because cooking is more creative?

As for your living situation at home - any idea when you might be able to move out? It just seems like such a negative environment. On the other hand, I would hate to see you suckered into taking care of such a big crabby family. It would be different if everyone pitched in and at least could be polite. But they don't seem willing to listen to reason.