Death in the family

It hasn't happened yet, but I'm going to be realistic and say my grandma will pass before Christmas. She has congestive heart failure and will not exercise or be active in any way, nor will she stop smoking. She has scheduled her surgery for December 8th but is to go into the hospital on the 5th. At least she'll have 3 days of no smoking. My grandma has literally given up. She told me herself that there's no point because her husband and mother are gone. We lost my papa 6 years ago in November and my great grandma this past June. I understand the depression, but to not seek help from the hundreds of doctors you see monthly or from the family that wants you to live, is beyond me. What hurts is that she doesn't want to be around to meet her great grandchildren. She's only 66. She shouldn't give up. I don't know how to handle this. I'm 6 months pregnant and I know the stress and negative emotions aren't good for the baby. And I know I can't make her change her mind. She's just waiting to go.