Hello Jenny. Your feelings about the loss of your friend are completely normal. I have a sister who is an alcoholic and I feel angry at her all the time. I know she is addicted, but I'm angry that she won't get help for herself. She is a diabetic so she drinks herself into a stupor and cannot give herself insulin. Many times we have found her half-conscious and near death.
So I just wanted to say that you should not to beat yourself up. It's not your fault and your feelings are normal. Your friend was lucky to have someone in his life who cared so much.