My Partner Of 20 Yrs Has Lung Cancer Its Been

my partner of 20 yrs has lung cancer its been there for 2 yrs it has now developed, in the other lung. He was told it was a slow growing, but of the last cat scan they say it is no more, for its in the other lung an in the limpnods in his chest. My question is... how do I know what stage he's in, an how will I know what to do when he gets so weak? He does;nt want chemo, he say he wants QUILITY time not QUANITY time.