My father passed awayand was representing himself on a dyed fuel case with the state of Illinois, what happens if I appear on his behalf but the state fails to appear
Unless you are the administrator or executor of your father's estate, you can not appear for your deceased father. A lawyer will be needed to represent your deceased father as the litigation proceeds. In all likelihood the Estate of your father will need to substitute for him in the litigation. Regarding the State not appearing, we would need to know more, including whether the State was properly served.