Had this same issue on my 2013 V7 Stone, a bit difficult to reach but was actually able to remove the nut and rotate the inner part. Not sure if our bikes are slightly different but didn't need to hold both. Gave it a full turn and boom perfect amount of freeplay. Will need to reapply some loctite to keep that nut in place.

Great advice and camera work!

My thought is it looks like there is way more adjustment room from the bottom where you have the camera. Or potentially unloading the back end by jacking up the middle of the bike would give you more room.

In my verry humble opinion this re-adjustment was not necessary as it seems to be a almost new bike with 5000 km's at most. The slack may have been a little to much but when you turn out the cable adjuster the clutch did disengage. After driving 10- or 20 thousant km's the clutchplates wear out al little and the slack gets less. There is often more damage done by clutch cables that have to little slack.

Next time, use a 12-pt 13mm wrench. It will give you more usable angles to work with.

This is painful to watch. Get yourself some better tools.