I am very sorry that your husband didn't get more time.
My 80 year-old brother has survived 10 years since his treatment (fingers crossed that he will get 10 more). He's still in great shape and engaging in a very busy schedule. He even has lady friends who clamor for his attention (but only in the nicest way.)!
It's possible I suppose his other ailments weakened his immune system and helped the cancer along.
The wonderful thing about it all, he never suffered horrible pain as so many do.
God is merciful.