Is the threaded copper a female adapter? If so, it might quicker and easier just to cut the adapter off, sweat a new one on and not even attempt to remove the broken PVC. To remove it, you'd have to make a couple of cuts in the PVC then pry the pieces out. You'd mess the copper threads up to a certain extent doing this which could make it difficult to get a leak free connection, and you'd not make very good wages saving the cost of a new adapter.