No Bamber, I cannot recall 5hat programme, but your excellent resume allows me to make an educated guess.
The tumour would almost certainly have been a malignant apendymoma and the survival rate would depend on the grade and extent of the tumour and also how much ofthe tumour could be removed by the neurosurgeon.
The boy may have had minor symptoms, headache perhaps, odd feelings in his legs and subsequent investigation might show that his walking and bowel and water control would be impaired.
I reassert that I didn't see the programme.
It is also safe to say, that it is unlikely that the child is alive today.