I was reluctant to join in this discussion in view of the outcome for robin,but i have to just say that while our head and neck surgeon muttered about chemo the oncolgy regiatrar dismissed it out of hand.He said it would diminish robs quality of life for his remaining time although your time is longer than his was.
Like you Georgia robs scans pre-op were clear and like you we were shattered to hear he had 4 lung mets.the similarity ends there really as robs neck tumour was so aggressive the lung mets never got a look in.

You are so very young(even younger than Rob was) that if it is only the lung mets that are threatening your life ,then i would insist chemo starts asap,and try to squeeze every last ounce out of life

good luck

liz