Your potting medium is severely broken down and rotting, and probably your plant along with it. You need to repot and take care of any rot on the plant. Remove the plant from the pot and clean off all the old medium. Trim off all the brown, mushy, dead roots and growths. I would soak everything in hydrogen peroxide until it quits bubbling, then repot in fresh medium. After that, keep the plant on the dry side until it shows signs of recovery and hope for the best.