Sounds like the poor thing was sheltered and beat but he is young so he can be trained! I had a siberian husky who would get scared or excited and pee. We had to teach her that was bad and to go outside to pee only.

For the smell, depending on if it's carpet or wood or tile would determine the best method for cleaning. Incense will virtually get rid of any smelly air so light one before friends come over for a quick fix. Training is not easy nor fast but worth it.