I am so sorry you are going through this. It’s a hard time of year being the holidays also. Regardless, it’s just hard. I would go see her for your own sake. You need closure. You deserve this. Like Don’t remember said, don’t drink over it. It will only add to the depression and make things worse.
I like Anna’s idea too. My therapist suggested that to me after my mom died. I saw her last breath. But similar to your situation, she was too far gone when I found out and I did not get to say goodbye. The letter I wrote was really helpful for my closure.