We are so sorry your plant is not recovering and we may be the bearer of sad news. The root rot may have been too advanced for any remedy, but was the potting soil a commercial potting soil or cactus potting soil (sterile and well-draining)? It appears quite dense – we hesitate to suggest you re-pot it and add about 20% perlite or vermiiculite to lighten it up because the plant has been so stressed, it might be at a point of no return. Perhaps at this stage, it is best to make sure when watering (about once every 7 days) when the soil feels dry down to the first knuckle that the water drains out without allowing the plant to sit in water (are there saucers under the plants – if so this may have been the problem). Also only feed with a slow-release or organic fertilizer (we mentioned this before) formulated for container plants. Again, the damage may be too extensive, but we are hopeful for you. One final note about transplanting, it needs to be at the same soil level as when it was in its original container.