Tears at death

My mother passed away 3 weeks ago. She had a massive brain bleed and swelling. She was on life support and had no chance of recovery. We were at a major trauma hospital and the neurologist said she had the second worse case he had ever seen. They told us she was in a morphine induced coma and I asked if she could hear us with all the brain swelling- and the doctor said no one could really ever know but that the tears were common in people in life support. They also told us she was technically brain dead but still had little activity and could take 6 breaths per minute on her own. Now to my questions- the tears coming out of her eyes were only every so often but her blood pressure would shoot through the roof when we talked to her. We made the decision to take her off the life support 12 hours later and I am afraid now that she was aware we were doing this. I always thought that it would be comforting to think they could hear us. But now that the shock has worn off I realize if she could then she would have know. Any advice, answers or experiences to draw from?