Dogs back legs going out?

We had a dog years ago that done the same thing got to were he coud not use his back legs and would pull his self around with his front legs. An elderly lady that lived down the road from the house came by one day and seen him and told my dad to put some turpentine down his back he put a half a bottle down his back in a few days he was walking never had a problem after that but it sliped the hair on his back. My dad told the lady that it worked but sliped the hair on the dog's back. Come to find out my dad used to much she said to dribble it down his back .