General aviation Flight Instructor reported the final approach course listed on the chart for Runway 30 at 12J airport is incorrect and/or the CEW VORTAC may be sending the wrong signals.

Narrative

My student and I were on the VOR/DME Runway 30 into 12J. Initially when rolling onto heading 300 from the CEW VORTAC to line up on the approach I noticed we were significantly off the final approach course that I should be seeing (not lined up with the runway). I let my student continue and just assumed he was still lining up on the approach. As we continued on the approach I noticed we were still not lined up with the runway even though my student was tracking heading 300 like the approach states to fly. I quickly made sure our CDI was aligned correctly and that the approach had us actually lined up to the runway because some VOR approaches have you fly offset and then break off to land; but this approach claims we should be lined right up on the runway. As we continue to get closer I did a quick VOR dual check to make sure the VOR receivers on board were both reading accurately; which it showed a good dual airborne VOR check. Then as we get closer I see if we continued on this heading we would completely miss the airport. My student also mentioned that the synthetic vision on our G1000 was showing a deflection and that the runway was not where it should be (it was off to our right). Since he was under the hood he could not see outside. At this point since I'm looking outside I confirm that we are too far left of the runway and have him look up to continue on the approach. My assumption of this is that the plate for the approach is not giving us a correct final approach course. It seems a 307 heading would be required for the approach. Or the CEW VORTAC is sending wrong signals.