Atleast you have an idea and can make a plan to treat him now. The worst is not knowing what you're dealing with. Addisons and Cushings are different sides of the same coin and we can create them with the use of steroids. Too much and we cause Cushings, reduce it after having them on it for a while and we can cause an Addisonian crisis. Problem is that its the mainstay of treating autoimmune problems, stuck between a rock and a hard place. I really hope he's doing better today and that you get him home soon, poor boy.