Well, if you do not get over your feelings about her, it is your mom's fault. I would be really angry. I do not know why she drinks and how sick she is. I have not being an alcoholic and I don't know what that means. My dad was a child of an alcoholic and he always resented that. That why he was so devoted although he did not do a good job with my brother. My father spoiled my brother. In any event, my father always told me stories about his pain for the irresponsibility of his own father and how he suffered from that. And I don't blame my father for his feelings, the same about you.
You did a great job and hope you can keep strong.i wish a fast recovery for your dad.
Sending you a big hug