Thank you, friends. We are still trying to figure things out. It turns out that there was an error with his blood cultures and he does not have a blood infection after all. He is a carrier of MRSA but apparently that is not causing the fevers because they can't find infection anywhere. They're now testing a theory that one of his meds is causing his fevers because the timing of the fevers is frequently within a few hours of getting this drug.
He has been off it now for 24 hours and is fever-free. It's still too early to know for sure, but I really hope this is it!