I assume you are speaking of the Struldbrugs. This is an account of the confessions taken directly from the text.
After this preface, he gave me a particular account of the Struldbrugs among them. He said, "they commonly acted like mortals till about thirty years old; after which, by degrees, they grew melancholy and dejected, increasing in both till they came to fourscor. This he learned from their own confession: for otherwise, there not being above two or three of that species born in an age, they were too few to form a general observation by. When they came to fourscore years, which is reckoned the extremity of living in this country, they had not only all the follies and infirmities of other old men, but many more which arose from the dreadful propect of never dying. They were not only opinionative, peevish, covetous, morose, vain, talkative, but incapable of friendship, and dead to all natural affection, which never descended below their grandchildren. Envy and impotent desires are their prevailing passions. But those objects against which their envy seems principally directed,are the vices of the younger sort and the deaths of the old.
By reflecting on the former, they find themselves cut off from all possibility of pleasure; and whenever they see a funeral, they lament and repine that others have gone to a harbour of rest to which they themselves never can hope to arrive. They have no remembrance of anything but what they learned and observed in their youth and middle-age, and even that is very imperfect; and for the truth or particulars of any fact, it is safer to depend on common tradition, than upon their best recollections. The least miserable among them appear to be those who turn to dotage, and entirely lose their memories; these meet with more pity and assistance, because they want many bad qualities which abound in others.
Thanks Mr. Jill D #170087 for the answer.....!!!