Pencil Cactus health
My pencil cactus has been going downhill. First, small little end branches were getting brown and then whole larger branches. Now the center branch is getting brown as well. I moved it from the corner to by the window to get more light and after looking online I stopped watering it. I haven't watered it for weeks but it seems to be getting worse. Any help would be appreciated!
A Pencil Cactus needs lots of sunlight and very little water.
Since your cactus is still declining, I would consider repotting it into dry cactus mix soil. You can fine premix planting mediums at most garden centers or even big box stores.
If the soil is very wet, you can even lay the root ball out on some newspaper to dry out for a few hours before repotting.
I would recommend a clay pot, as this will help absorb excess moisture.
If too much of the root system has suffered root rot, you may not be able to save the plant.