The great news is that we’ve definitively ruled out GVHD, and looks like very treatable gastritis. 
The less great news is that Sam’s been running a fever since Thursday afternoon that we don’t know the cause of yet. He’s on antibiotics and about to start antifungal. If he’s still got it tomorrow we will get a CT scan to look for any signs of infection. 
So generally good, but here until Monday at least. Glad we are here, honestly.