The correct name for the part where the freewheel mounts is the hub. The rim is the part where you mount the tire. Here's a picture of the two designs (freewheel/cassette) so you can see the difference. Most newer bikes use the freehub with the exception of some inexpensive bikes. I doubt the owner damaged the threads prying off the freewheel but cross threading the freewheel and damaging the threads on the hub is far more likely. If you can't thread a new freewheel onto the hub straight then the hub is toast. I doubt bike shop will have a tool to fix the threads though there is a solution here: chasing a freewheel thread plus axle question If you do it carefully you may be able to salvage the hub.