I don't want to take care of my dad who was diagnosed with alzheimer's
Who's going to take care of him?
My grandparents will take care of him. They are his parents.
You should be there for your parents when they are ill. You should stay there with your dad and not force all the work on your grandparents.
Nah. My grandfather will take care of it. Grandparents should take care of the kids.
But they will eventually die and no one will take care of them. Allow your grandparents to enjoy their old age and get a caretaker to help him if you will not.