I would put it on my answering machine. 'If you are calling for 'blank' this is not his telephone number. He no longer lives here. Please take it off of your list. And if you know his number-put it on there. I don't know if that is legal. But I bet he won't use your number anymore.
-------------------- Message for my ex "I think you know by now, I'm not the person I used to be"