Hi Sara its seem that your plant is relatively dehydrated as a result due to issue of watering and could be surrounding very hot and windy. Base on the photos I would say the roots most of them were not that healthy and the moss that you covered the bottom of the roots could be contaminated with some pathogen like bacterias . My suggestion you need to remove the dead roots thoroughly, spraying the plants with fungicide/ organic insecticide put under the shade say less than 50% light, spraying the water 3 to 4 times a day depending on your climate if very hot the frequency to be increased, at least about a months until the new roots emerge from the plants. keep the plant into the big pot and tight it very nicely. The dehydrated leafs nothing much that you can do until the functioning roots begin to work that the issue over need to be patient.