What can be done if a 5 year old male's fever is not responding to i.V. Antibiotics?

Re-evaluate. If the child is not responding to IV antibiotics, this might mean that 1) the correct antibiotic for the organism is not being used 2) a bacteria is not the cause and will, therefore, not respond to an antibiotic. The most common cause will be a viral infection, but other causes such as autoimmune diseases, drug fever could be considered.