Mr. Silver,
What a heck of a year for you guys. Ok, I am responding as first a person with alot of sick and dead relatives from addictions, second as a hospital based licensed social worker, and third as a certified addictions counselor.

Whoa.
My grandfather went through this process. My father went to every store that sold liquor in walking distance of my grandfather's independent living, told the store owner about the alcoholism, and threatened to have them legally charged with accessory to murder if they sold him alcohol and he subsequently died. Reality, he couldn't do this, but they didn't want the trouble. My grandfather got another resident to go buy it for him, he passed out, hit his head and died of pnemonia in the hospital during that stay. Your mom's drinking appears clearly out of control, hers, the facility's, and yours. The facility that she lives in cannot "kick her out" without due process. They would have to evict her and this is difficult. They CAN threaten to toss her hoping you'll take her out or that she will leave, but they cannot legally kick her out just for drinking. Check her living agreement there and inform yourself.
They are hoping you will control the behavior. Even nursing homes cannot kick out residents for these behaviors. What they CAN do is try to dump her at a hospital and state that she is not fit for their level of care, which she appears to be, or try to get you to take her to your home. Either idea is bad. She is troubled from the loss of her husband and by her alcohol use itself. An intervention is probably the only way to reach her.
At this point limiting the alcohol, getting rid of what you find, will slow it, but also make it more hidden. It will make you feel better for a bit, but there is always someone who will go buy more for her and feel sorry for her that her son keeps "stealing" her alcohol from her and won't let her "grieve." She probably does not see that you're trying to help her, yet.
Lastly, my FIRST client was an 82 year old grandfather whose family had convinced him that he wasn't going to get to see his grandkids anymore if he didn't get help and stop drinking. He came for 28 days of inpatient treatment, got sober, saw his grandkids and was still living and sober ten years later. I lost track of him after that and likely he has passed since then. He was a happy man who let go of his guilt and learned to live, and I mean really LIVE, without alcohol. Not all stories turn out like that, by far, but he did and so have others.
As to your role, that is up to you. You have to decide how much more you can take. The process to get someone into treatment can be difficult. It can be rewarding. If your mother's alcoholism is interfering in her life and yours, you both will eventually need to talk about it. If you decide to do an intervention, make sure you get a professional to help you with this process.
I wish you the best. There is nothing wrong with going on as you have. This is your mother's disease. She is responsible for the outcome and even with intervention, there is no guarantee. Bottom line, she determines the outcome.
Remember you did not cause this illness, you have not worsened it, and you cannot cure it. Just love your Mom the best way you know how. We are all here for you.