I have this plant(dont know its exact name) and had spider mite. However after spraying it seemed ok. Today it felt somewhat soft. One of them came out without much force. Is this a root rot? What can I do? I watered it with anti-fungal.
If the second picture shows the roots or what is left of them you bet this is root rot. You plant looks healthy, new leaves as well. Except for the root rot bit. Did that come out of the same pot/plant? I would transplant that plant into fresh potting soil after bleaching/cleaning the pot.
Too much water. Don't allow the plant to sit in a water filled saucer. Don't water unless the pot/soil/plant feels light when you pick it up. Your other plant looks like a complete goner. Sorry. Too much water will kill plants. Too much fertilizer will kill plants. Too much light will kill plants. Too much love meant for humans will kill plants.
Are these plants in potting soil? Did you happen to put gravel below the soil above the drain holes? That makes drainage worse than no drain hole. Raise the bottoms of your pots off the surface with bits of tile to get air beneath the pot.
I would transplant both plants in fresh potting soil, moisten the soil, feel the heft of those pots while moist and only water when those pots are light. You'll easily feel the difference. We can talk about fertilizer later.
It does seem to me by the photos that it could be root rot, but really hard to say 100%.
The best advice i can give you is to remove the plant from its pot and make sure you remove as much soil from the roots as possible, washing the roots gently is the best method for soil removeal. after replace the soil with fresh heathy uncontaminated soil.
i have searched the internet and found this helpfull page for you from the gardening know how website.
Good luck and post an update on your findings