You have to ace the test (by picking all of the top answers) and he will ask you to tutor him. Meet him everytime he's by the trashcans/anywhere else, and help him find Canada when he goes missing. If that doesn't work you can tell me and I'll replay the Russia ending and update this response for you. :) also, I have gotten every ending except for the second Japan ending (can't figure it out), so I can help with other runs if you need it. :)