Subaru - Legacy :: 1995 - Wheels Seize Up On Using Parking Brakes

My mother in law gave her 1995 Subaru to us last year. She told me not to use the parking brake because the wheels seize up and to drive it often. We did not need a third car and every third day of not driving it the rear wheels would seize up which would require me (once in the snow) to jack the car up, take off the rear wheels, and tap the drum with a large hammer. Doing this would cause a huge mess because of the rust which fell onto the driveway. So recently I told her that the drums, shoes, and most likely the brake lines needed replacing and I would not pay for that as I didn't need the car anyway. Her response was that If I had driven the car every so often then it would have been fine. At which point I raised the safety issue with the braking and so forth which she flat out rejected saying it was fine when she drove it. Now I'm being blamed for the problems with her old neglected car. Should I just have the thing towed away or try and get it fixed?