Boy, Pard that's a rough one. I was very fortunate, both of my boys were great. One love shooting, so I took him to rifle matches and we shared a rifle and gear, when he was 13. He is now 37. We also did a lot of hiking and photography. My other son is now 41. He is a very smart guy and loved computers and he still makes me a very proud father. I think you have to find something that Brad may be interested in and join in with him with that interest and show him that you love him. My boys did not get spankings after they were about ten. I think after that it does not work. Showing the results of doing things right or wrong will do more good. When you go to the tutoring you might make it a WE thing instead of you. Talk about what you learned with him.
Dave