What does Paul tell Boy? What does Boy remember of his childhood?

Paul tells Boy that he was Mrs. Dempster's son, and the same child who Boy tormented. Boy claims he does not remember any of it,

“No. I don’t remember what is of no use to me, and I haven’t been in Deptford since my father died. That’s twenty-six years.”

“You have no recollection of Mrs. Dempster?”

“None at all. Why should I?”