This must feel terrible, however I would not rush here and guess prognosis, these days even refractory has a real chance of being beaten.
It is also important to remember that immunotherapy often can shrink tumors.
I would recommend asking if MIBG therapy makes sense, asking if LUDO trial on SIOPEN makes sense and so on. Also given how complex this is maybe contact Spain they have access to hu3f8 which is a more potent immunotherapy drug than CH14:18