Why do my adult sons not care enough to take me to the hospital or get me food and water?

I imagine that Jack posted on his grandmother's behalf. Perhaps in a moment of blazing indignation. One can only sympathise.

And the original poster never came back to add any information or comment.

This does not make sense. If the person can post they are able to call an ambulance. If in independent living, there r people the person can contact. Weird.

This is on Jack's profile: "I am caring for my grandmother, living at independent living and the primary ailment is alzheimer's / dementia."

Have you asked them? Some need to be asked. I know a lot do it automatically, but not all.
Do they live with you? Near you? What are you capable of doing for yourself?

How about looking further a field. Support workers. church, doctors? ANY outside agencies?

It would help to know a little more about your situation. Then some of the experts here will be able to offer real advice. Good luck.

What do they tell you when you ask? It's hard to know without knowing anything about your story. Some parents are awful to their children but expect their adult children to take care of them when they need help. We read about that on this board every day. Some parents are overly indulgent with their children and their kids never mature to accept responsibility as adults. It could be either of those scenarios. How old are you and how old are your adult children? Do they live nearby?

Whatever their reasons, it sounds like you need to find some alternate means of getting yourself the care and support you need. Do you have friends who would help out or a faith community or any volunteer organizations in your area?