No treatment left

My friends gorgeous boy has been fighting brain tumour for 4 yrs - after 1Yr of being cancer free thanks to a yr of chemo b4 that it had come back with a vengeance and we have been told there is nothing left in the box of tricks. Devastated - for him for his beautiful family and for me as this young man is like family to us. How do you help a 16 yr old with this ? How do you help the family - what helps what doesn't - so cross with the world and so so sad