Ascites is a
symptom of another condition. Many things can impact the liver negatively. Most posts ask if there is
abdominal bloating which can be ascites, matter build up in the abdomen from infection/internal laying, or tumors/cysts. Once a bird is ill (usually gravely) the immune system is struggling already and things can snowball, often ascites will accompany other conditions due to stress on the circulatory system and liver. So if there is ascites then the liver is in trouble, but the reason for that trouble
may be ultimately another cause rather than straight up liver failure with no other health problem. There are plenty of posts of birds that also presented with ascites and necropsy shows loads of visceral fat and a very unhealthy, friable liver and sometimes large clots of blood from fatty liver hemorrhagic disease. So the underlying cause of ascites can be varied, and it's often very difficult to put an enormous amount of information in a relatively short post on this forum. I would suspect that if a bird is/was having difficulty with a wormer medication affecting the liver that there was already another health issue that was negatively impacting the liver function, or the dosing was incorrect for the weight of the bird.
https://www.fresheggsdaily.com/2017/06/water-belly-or-ascites-in-backyard.html
https://www.merckvetmanual.com/poul...itions-of-poultry/ascites-syndrome-in-poultry
https://www.merckvetmanual.com/poul...f-fatty-liver-hemorrhagic-syndrome-in-poultry