You can't hide your true colors as you approach the autumn of your life. ~Author Unknown
Growing old requires grace and courage. Aging is a series of insults that you have to take in stride else you become a distasteful burden to yourself and those around you.
Grace and courage are not attributes the narcissist possesses at any age so the lack of these virtues become all the more apparent as they grow old.
You don't have to live terribly long to observe that age highlights and underlines what you've been all your life. I have met delightful elderly people who are so lovely on the inside it makes their wrinkled faces a pleasure to look upon. I have met the others...those whose wrinkled characters are unfavorably enhanced by their craggy countenances. They become odious inside and out to the observer.
The final act on the stage of life seems to be a pulling back on the curtain of the soul. For some, age seems to have taken them by surprise. The series of choices that brought them to old age were not choices that ever anticipated this part of their life. They are bereft of any qualities that would make them capable of being content at the time of lessening that we call aging. The decrepitude of their character is fully exposed by the decrepitude of their bodies.
Narcissists do not age well. Whether they depended on their beauty or their intellect, they now find themselves unable to summon the charm or sophistication which enabled them to lure in their sources of supply. They are pathetic and lonely. Neither their bodies nor their minds are impressive in any sense. Withered and shrunken, their minds and bodies are now betraying them. They are daily confronted with the huge gap between what they fantasize themselves to be and what the mirror on the wall and the mirror on your face reflects back to them. The "grandiosity gap", the distance between the narcissist's grandiose vision of himself and reality, is now a yawning and unbridgeable chasm. Constantly angry and dysphoric the narcissist is a curmudgeon that most have abandoned.
It isn't your imagination that your narcissist parent is worsened with age. This is the normal and usual progression. What you are witnessing is a three year old trapped in an old man's or old woman's body. The temper tantrum that could pass for cute in a toddler is shockingly and monstrously detestable when performed by the aged. Old age has stripped away the cover that enabled her audience to un-know that an adult was acting like a pre-schooler. No beauty to distract us. No soaring heights of intellect to dazzle and confuse us into compliance. The emperor has no clothes. The sight of the "naked" narcissist almost makes you want to gouge your eyes out. Hideous.
The narcissist has been in a life-long battle to defy death. They pretended for years that death could be avoided by refusing to acknowledge its inevitability. I have been struck by the abject fear the narcissist shows when they are forced to contemplate their own mortality. Why is the narcissist so afraid of death? I think the answer is that they fear obliteration and Judgment Day. I think the extremely deprived conscience of the narcissist is never quite able to dismiss the idea that there may be a Day of Reckoning to meet in the hereafter. They would avoid that Day, not by actually making restitution for wrongs done, but by refusing to die. Some of the most tenacious clingers-on to life are narcissists.
Some elderly narcissists are so evil and nasty that families find that outside agencies will refuse to deal with them thus leaving the family with no options but to care for the wrinkled beast themselves. If you are dealing with an aged narcissist, you have my deepest sympathies. The enraged and elderly narcissist will find no respite until they are in their coffin. Neither will you.