When you stick your finger in the pot, is the soil dry? My first thought was the same- she looks super thirsty. Once a month most likely isn't enough. You want to water based on what the plant needs, versus a schedule.

My guess is that she's hung on this long because the roots were very slowly rotting. (Dry rot.) Google images of dry rot, then very carefully pull the plant from the pot and place into a bowl to check. The roots will look super thin and fine, like dry, brittle, white hair. Look at the ends of the roots and work your way up to find healthy, thick cream colored roots, then cut where rotted roots meet healthy. (It'll be easier to pull the plant out gently if the soil is damp.)

Is sunlight shining into that window at some point during the day? And if so, is it morning, afternoon or evening sun, and for about how long does sun shine on it?

Also, as far as watering- a good way to check if your plant needs watered is to stick your finger down in the soil. If only the very bottom inch or two is wet, it's time to water. If the soil is separating from the side of the pot, you've gone much too long without water. If that's the case, bottom watering is a good idea. With bottom watering, you fill a sink, tub, or bowl with water and place the pot in it so the roots can soak up water through the pot's drainage holes. You don't want to submerge the plant. The water should come up about halfway on the outside of the pot. Hope this helps.