My advice would be to have a good friend collect the stuff from him. First decide if you really need it in the first place though. Another suggestion would have him box it up and leave it in a safe place for you and vice versa with his stuff. People do often use the "stuff" as an excuse to contact each other.
Unless something you have of his or he has of yours is an irreplaceable family heirloom or something really, really important and hard to replace (like a passport), I would put his stuff away in a box on a high shelf in a closet
Unless something you have of his or he has of yours is an irreplaceable family heirloom or something really, really important and hard to replace (like a passport), I would put his stuff away in a box on a high shelf in a closet