That would be a question best answered by his doctor.
My son is in hospital, we went this morning and he has a scan and was told he had fluid near his appendix. What is this and what can be done?
Definitely the doctor who is in charge of his case is the only one to tell you precisely what that means.
On the other hand, it might simply mean that the primary finding was the edema and it might have made the CT less useful for differential diagnosis than he had hoped. (Apparently, fluid that shows up on an abdominal CT is not necessarily an ususual finding.)