How can I help my aunt handle her grief?

Our family is a very close and we lost my Grandfather on 12/11/08 and just recently loss my aunt to lung cancer on 07/28/09. My family is going through a very difficult time since it seems as though we just lost my grandfather. One family member in particular worries me. My aunt took care of my grandfather as soon as we learned that he had dementia and on top of all the other health problems he had she eventually had to take him to a nursing home. We all visited regularly and when we learned that he only had a couple of months lived we all decided that we did not want him to pass in a nursing home. She volunteered for him to go back home with her, which was very close to all of the family. When trying to regulate his medication to make him more comfortable hospice suggested that they take him in until they can do just that. Within a week my grandfather had passed. She took it very hard as we all did, but even worse because she had told him that she was going to bring him back home. During that whole ordeal we had learned that one of my other aunts was diagnosed with lung cancer. After my grandfather passed she had asked my aunt that was taking care of my grandfather if she could help her go through everything that was about to change her life. My aunt then promised her that she would be a part of it all. Within the last three months of my aunt's life she was in a nursing home,just as my grandfather. Due to all her pain that she was feeling due to some tumors that grew in her brain it was the best thing for her. Then on the 28th of July she also passed in a nursing home. Now I am worried that my aunt is just going to be completely depressed due to feeling like she did not live up to what she promised my grandfather and aunt. She is sleeping all the time and distancing herself from her family more and more. I dont know what I can do or say to help her. What makes it even harder is that my Grandmother is still a live and currently living with her now, so she is afraid of letting my grandmother she her "weak." I want to help badly but dont know how. My other family members tend to stay away from situations like this and ignore that they are happening. What should I do??