Sorry for what appears to be an enormous journey. I have been diagnosed 3 X in the last 24 years but my experieinces don't begin to compare to what your husband has been through. I don't have answers for you on your situation, just to tell you that I and others here can offer mental and emotional support, as we understand what your going through. I lost my Mother and Father both to cancer 10 months from each other, I believe it's just as hard on the caretaker as it is on the patient watching someone you love dwindle down to nothing.
As a patient 3x and being there before, I appreciate the efforts of caretakers to make us as patients feel as best we can, and I thank you for being a great caretaker.
I wish you both the best.