Oh man. Axle nut is just spinning and won't tighten or come off. Plus there's no room for a rethreader at the end of the axle.
At the risk of losing a good wheel and a Swiss bearing.
What to do? This is an old thread, but maybe someone has come up with some tips/experience in the meanwhile.
The best way to get this off is to pull the wheel up / outwards / away from the hanger as you spin the nut with a skate tool, so this will push the nut up onto another thread and maybe get it to bite and then come off.
Most of the time it is just the nut itself, occasionally it can be the hanger axle, but at least the nut is the softer metal and often more easy to manipulate through use of some force without smashing it or having to cut it off.
I had done this before by standing the board side on, feet sort of standing on and holding down the ground side wheel, then one hand pulling the upper side wheel upwards and the other slowly turning the nut with a skate tool, which worked and got the nut off, rethreaded and replaced with new nut and was good to go.
Might work, but also might not, depending on what was going on with your own setup.
Good luck!!!