Thoughts on possible imminent death for my mother

So - I am reading Pharyngula, the best science/atheism blog, and there is a very good thread going on there right now - Cancer is a disease. It is not an easy thread to read, many people sharing their pain and stories. I tried to enter into the thread, came on too strong offering help, and have now backed away entirely. I still read, but I will not comment.

The reason why? Well, one, I was too strong, too eager. In retrospect, I looked like a stalker. Two, the ongoing saga of my mother is at another potential breaking point. Death may be imminent, at least within a few weeks. Simply, she keeps pulling out her stomach feeding tube, will not take anything by mouth, and thus is malnourished. She also seems to be losing the ability to fully metabolize her food. My sister is there, doing most of the decisions, killing herself in the process. I try to support her - no, I do support her. Dr. asked Sis today if she wanted him to try and put the feeding tube back in, i.e., feed her or let her die. Sis said to put the tube back in. Neither Sis nor I believe in needlessly extending life, and mom has a living will forbidding heroic measures, but we are in a gray area. Mom is awake, sometimes lucid, sometimes alert. Were she unconscious, comatose, of the like, the decision would make itself. Now?

My impulse is to pull the feeding, let her slide away, and hasten it with an overdose. I do not think her life is good right now, has not been for six months. She will never walk again, never go home. She may never even leave the hospital and if she does it will be to a full care nursing home in which she will spend her life in bed, sliding further and further into dementia and growing frailer, waiting for the next trip to the emergency room to attend her next feeding tube failure or infection. I have serious doubts she will leave the hospital this time. How much pain do we put her through seems to be the only real question.

I thought of broaching the subject tonight, but Sis sounds so tired. I know I have to bring this up soon. We need to talk about it. I need to get my foot fixed so I can travel as needed. Lots to do. I know there are lots of things to do, right now I just do not know what those things are.