No need to tell "M" about the couch. That would just make "M" mad without being able to do anything about it. But as a friend you might want to keep your eye open for any packages that get delivered there. If you're friendly with them then you can just go over there and say hello and let them know that "M" asked you to help keep an eye out for the package too. That might help to keep them honest if they know theres a chance you will know when the package arrives. I agree with bbnbama that the less you are involved the better.