Preparing myself for the end

My husband and myself are 40. He has been diagnosed with life ending cancer. It is quite extensive. Last August we were told stage 4 lung, lymph nodes, spine, hip and thoracic. This year it’s spread to more bones, stomach lining and liver. My husband is completely in denial about his palliative diagnosis but I’m aware and happy to help him think he will survive. I’m heartbroken but I’m off work as a carer which I am grateful to have this time together. My main concern one I’ve been nervous to ask is what should I expect to happen near the end. Right now he’s being treated with palliative radiation for severe pain. And chemo to lengthen things. Any advice please would be appreciated.