How can I help my husband face the possibility he may not survive?

My husband was diagnosed with locally advanced/borderline resectable pancreatic cancer on April 11th. His oncologist recommended a chemo regimen aimed at shrinking the tumor so it can be removed with Whipple surgery; unfortunately, chemo treatments had to be postponed two months due to a number of complications related to the cancer. One of those complications is Cachexia (Wasting syndrome). He has lost over 20% of his normal body wait and has signs of muscle wasting, too. He has now had 3 chemo treatments and is not tolerating them well at all. He loses more weight and becomes weaker each time, and the oncologist hasn’t even started giving him the full dose of chemo drugs because he isn’t sure he can take it.
My intuition has been telling me all along that he is not going to survive this with any quality of life left, but haven’t been able to talk to him about it because until recently he has been convinced he can beat it and get to the 5-year mark. Lately, though, his suffering has caused him to realize he may not have much time left, but he still seems afraid to talk about it. If he mentions his mortality and I try to discuss it with him, he gets angry and shuts me down. I am afraid, too, and also filled grief for what I know is going to happen.
I realize he needs to process things in his own way and I want to provide the right kind of support at the right time. My hope is to help him make peace with death before it’s too late. Can someone help me with how to do that?