Legal advice about my grandfather dieing and aunt making rash decisions.?

I was just talkign to my grandfather fine less then 2 days ago. He callapsed in the street a few days ago in NY and they took him to the hospital. His lungs are filling up with liquids and doctors dont know why. Right now they have him in a induced coma so hes not in pain. My Aunt which no one in the family really speaks to is making a decision to take him off support and letting him go. Everyone in the family believes shes doing this for the money. No one in the family agrees with her dicision Exspecially with it not evne being 24 hours. What can we as a family do to overthrow her decision or do something. My grandfather has fought off cancer several times and is a fighter.