Hi, I am a 31 year survivor of stage 4+  NPC. I was 15 at the time.
Back then it was very rare. I was the 5th in UK to have it, and I know of 3 ladies in USA who had it around the same time and have survived.
Nowadays it is not so rare sadly, ,(around 240 per year in UK alone),  but there have been huge improvements in treatments, ( so he won't have many  long term side effects, as people like me who had very high dose of radiotherapy blasted at us have) and survival rates.  There is 80-90% survival rates nowadays and at least 50% of no recurrence within 5 years. There are lots of us in facebook support groups who can answer your questions and give reassurance, but feel free to message me too.
I know it is daft to tell a mum not to worry, but please take it one day at a time .

Hello I am a stage 3A NPC survivor in the uk I was diagnosed at 11 and believe I was the first in the UK as a child to be diagnosed. Treatment was aggressive and the worst part I was allergic to my chemotherapy and then also thr antibiotics to counter the allergy. Radiotherapy was much tough as the effects of losing my thyroids and saliva and petuity glands. But the end product is I’m still here and positivity is what I believe made all the difference(along with a strong woman as a mother that will never give up)

Hello I am a stage 3A NPC survivor in the uk I was diagnosed at 11 and believe I was the first in the UK as a child to be diagnosed. Treatment was aggressive and the worst part I was allergic to my chemotherapy and then also thr antibiotics to counter the allergy. Radiotherapy was much tough as the effects of losing my thyroids and saliva and petuity glands. But the end product is I’m still here and positivity is what I believe made all the difference(along with a strong woman as a mother that will never give up)