your description sounds a lot like my ex-husband. My ex- did finally agree to go to marriage counseling, but our counselor recommended that he come for individual session to work on issues and he refused. It could be "our" problem, but nothing was just "his" problem - but it was.
I started going on my own and that helped me immensely. I learned how to set boundaries, stick to them, respond more neutrally to him. My therapist helped me realize that his problems were his, his choices were his - that all I could really control were my choices.
this process helped me emotionally separate myself from him when he was yelling, trying to fight over nothing, etc.
Also, I was confident that by the time I did file for divorce I had given him every chance to work on issues, and had clearly communicated to him for a long time how unhappy I was in the marriage.
His health is not your problem, plus you could still be there for him if you wanted to even after the divorce. My ex- and I get along fairly well now and we do help each other out when needed.
There are consequences to our actions and choices. If his choices have led you to divorce, then his consequence would be being alone. Don't feel guilty for that, you have every right to take care of yourself!
You might find going to a therapist on your own helpful.