rogerw: May we please have the context for this sentence? Who is saying it about whom, and in what situation? (What has just happened that provoked this comment?)
Without context, we cannot know if it means "he has cooked someone else's goose", or "he has cooked his own goose".
My dog has had his freedom to roam around and greet people on a motorhome park in Portugal. He is generally very friendly and well liked. However a new dog has arrived which he took an instant dislike to and he became agressive towords it. As a result he has now been tied up. He has cooked his goose.