Out of curiosity, I looked up the definition of illness. Seems to be so loosely defined that it can be either a disease or a patient's personal experience, including "lethargy, depression, loss of appetite, sleepiness, hyperalgesia, and inability to concentrate", which (possibly excluding hyperalgesia, I've not heard of that before now) are associated with aging.

Regardless of if "illness" is or is not a terminological inexactitude, it looks like ageing is a chronic progressive terminal genetic disorder. I think "cure" is an appropriate term in this case.

Involuntary ageing is the very worst tragedy of human life.

Funny that this kind of ideological conflict will likely be a key fulcrum of the machine intelligence revolution. We will have a very loud minority that attempts to forcefully prevent all other humans from having the voluntary choice to avoid suffering.

Are you in it?