The white coating could be fungal so get some fungicide. Check that the media in the pot isnt rotted and wet. Roots need air circlation. Trim off rotten roots - these are brown and mushy. Looks like it has potential under right care to mature and the new shoots a good. sign. The white could also be mineral deposits, salt deposits. Try rainwater to flush it. Dont overwater and fertilize with weak amounts. wash plant a few times to rid all trace of scale insect. Other than that your good to go. Place in strong light.