Depends on the 89 year old. Some are as sharp as a tack, while others don't have a clue where they are let alone what they are currently doing. If you don't understand that, you clearly need to widen the range of people you interact with beyond your day to day experiences thus far in life.
I am in the middle of watching my own parents age, and it is eye opening. We have checks and balances in various systems exactly because there is a wide range of capabilities in the elderly. Where I live it is mandatory for drivers to be tested regularly once they hit 80, or at even earlier ages in the event of an accident or other precipitating event. This can include recommendation by doctors, social workers or even police. This works without needlessly discriminating against individuals.
I am in the middle of watching my own parents age, and it is eye opening. We have checks and balances in various systems exactly because there is a wide range of capabilities in the elderly. Where I live it is mandatory for drivers to be tested regularly once they hit 80, or at even earlier ages in the event of an accident or other precipitating event. This can include recommendation by doctors, social workers or even police. This works without needlessly discriminating against individuals.