Who is the protagonist? What makes the character dynamic, flat, round, or static?

I would argue that the protagonist in "Contents of the Dead Man's Pocket" is Tom Benecke, not least because he's the only real character in the story. But as well as being the protagonist, he's also the antagonist, and this makes him a dynamic character.
When the story begins, Tom's staying at home in his apartment while his wife Clare goes to the movies. Tom feels pretty bad about letting Clare go all by herself, but it's so important for him to get a promotion that he needs to stay home and complete the research he thinks will land him a better-paid position. Initially, then, Tom is fanatically dedicated to his work to the exclusion of pretty much everything else in his life. This explains why he's prepared to risk his life to go fetch his research paper when it blows out of the window and onto the ledge.
But over the course of the story, Tom's attitude changes, and this is what makes him a dynamic character. He comes to realize that work really isn't the most important thing in life after all. It's taken up too much of his time, time that could've been better spent with his wife. Tom now fully appreciates the value of time, something which his workaholic nature prevented him from doing. His whole character has changed, which makes it dynamic.