We have a reason

Yesterday I found out the reason for the problems Seth has been encountering. He has Graft V Host Disease through his digestive system.
By Saturday the doctors said enough is enough with his temperatures. They made the decision to start him on steroids which drops his temperatures and is what they would do if he had GVHD. They were taking a small risk in that if it was a virus he had, then they would be taking away the body's ability to fight the virus - which is temperatures.
The temperatures dropped immediately and have been normal ever since. He still suffers from nausea and vomits here and there and he also still has the runs.
The doctors went ahead with their endoscopy and colonoscopy on Tuesday and they couldn't see anything abnormal so I was left wondering what on earth is going on and hoping it wasn't a virus after all. They took 6 biopsies and sent them to the lab for testing and we found out yesterday that GVHD is confirmed. What this means is that Seth's body is unable to absorb any nutrients from food. He has been unable to keep things down, and what little he did keep down went straight through. This accounts for the rapid weight loss, the vomiting, diahorreah and the very high temps.
Now they know what they are treating, they have changed his steroids to one that just sits in the gut as the steroids he is on at the moment have made him extremely lethargic and he is just sleeping all day long. They are increasing his immunosuppressant drug as well, just to get him past this hump. 
They also ordered a PET Scan yesterday which was quite interesting - we had to go to the adult hospital and they put radiation into his blood. I then had to leave the room because he was radioactive and sit behind lead doors for 45 minutes while he stayed there watching tv. After 45 minutes they took him in to be scanned in a big donut, then 10 minutes later it was all over and we were able to go back to our room. We have no results from the PET Scan yet and I'm not really sure what they are hoping to find or rule out. Seth's temp got to 37.5 this morning, so I am just hoping it doesn't get any higher and we will be home soon.