Last year, it was Terry Pratchett. But this year it was Gene Wilder. And now we have also learned Terry Jones of Monty Python is afflicted. Because this disease shows no mercy. As much as we love these entertainers (and Jones is a medieval studies scholar), Alzheimer's just plain does not care. But we do.
The term 'pantsing' refers to flying by the seat of your pants. So essentially you write with very little idea of plot or structure. And the intention is to fix it later. For the most part, I write shorter stories this way. However, they might be part of a larger overall story arc. Hence the actual writing might end up a tad haphazard but the scene or scenes fit into a greater whole, which has been planned.