I can't add much to what the others have said, only wanted to tell you that even thought you feel alone, you are not......A lot of us have had to deal with a loved one having been diagnosed with cancer and I can tell you that it is hard to face, even if the prognosis is good......My feelings are that a big part of the reason our loved ones are addicts in the first place is because they cannot face life on life's terms.....If you ignore it and get high the unpleasant things will disappear....the reason I am saying this is because he is not there for you because he cannot....it does not mean he doesn't care, it only means that his addiction is stronger than he is and it is telling him why face the bad stuff when you can block it all out with a fix.....I will be keeping you in my prayers.....
Peace