Rock Bottom in a Long Distance Love With Stage IV Bowel Cancer

Having searched for months, I'm relieved to finally find this safe place.  I'm looking to share how broken I am in my relationship.  I have been in an loving LDR with a lovely man for 2 years. My soul mate.  A year ago he was diagnosed with Stage IV bowel cancer, and has been having palliative chemo. This has recently been stopped for various reasons.    My struggle is that I'm slowly watching the man I adore become insular, closed off and often selfish. Emails and calls are increasingly all about him, often laced with rants and anger.  I quietly and gently say I love and care deeply.  It no longer seems to register.   He is showing less warmth and affection.  Last time we met he was so withered, self conscious and distant.   The change in him frightened me a little.  

I cry myself to sleep every night. There is no possibility of us sharing what time he has left. He is much, much older than me. He has a caring family around him, but I have yet to meet them. I can't be with him for treatments and appointments. The avenue of online and calls and the odd meeting is closing.   I am so scared of how much I am losing him.....even though he is alive.

I just don't know how much longer I can keep digging deep,  biting my tongue. I walk on eggshells with all my words.  I feel mighty guilty for wanting a little warmth.  I know and appreciate he is in a dark and difficilt place.  I just don't know what else I can offer.  I am so in love with him and don't want to walk away.  But I feel my own spirit sinking, feeling helpless and sometimes taken for granted.   Do I keep telling him I am here....or do I loosen the my hold and let him come to me if he needs me ?

I just need frank pointers, some support.....maybe a little hope. xxx