You do not clean your beardies cage every time it poops? If that is so then you really need to reconsider having one. That is way irresponsible and I cant imagine what your tank looks like. I'm sorry that im coming off blunt but that habit needs to be changed right now.
Are you also not seeing the main problem? FOUR beardies in a small tank, that is a recipe for disaster. You shouldn't even have ONE beardie that size in a tank that small. Not to mention I highly doubt she gives them the correct uvb and supplements, or the right amount of food. I can't believe that those are still alive, im guessing that they are all the same sex because if not she will have dead beardies very soon.
Id keep going but I do not want to write a caresheet...
To the op- Maybe ask if you can help change/correct things? And if they refuse your help then do something.