My father in law was diagnosed with lung cancer aged 85 too. Here's the thing, they decided that any treatment would most probably kill him sooner. Chemotherapy can be brutal,although much improved nowadays. My father in law was able to have a good quality of life for another 4 years and died peacefully aged 89. 

It's not always about not thinking a person who is older isn't worth treating it can be kinder to not put them through an ordeal, is what I am trying to say.

Big hugs to you it's horrible feeling helpless and you grieve while they're still here in many ways.

My father in law was diagnosed with lung cancer aged 85 too. Here's the thing, they decided that any treatment would most probably kill him sooner. Chemotherapy can be brutal,although much improved nowadays. My father in law was able to have a good quality of life for another 4 years and died peacefully aged 89. 

It's not always about not thinking a person who is older isn't worth treating it can be kinder to not put them through an ordeal, is what I am trying to say.

Big hugs to you it's horrible feeling helpless and you grieve while they're still here in many ways.