Question about the Chafetz Chaim

Someone came to Chafetz Chaim to ask for a blessing. He had severe stomach pains or a stomach ache, I think. The rabbi inquired with him that he feared God and was careful about everything, but he had a son who had bought a taxi in Radin and would drive people on Shabbat. The Chafetz Chaim told him that regarding Shabbat, it is said, "Go and let us go," because it is the source of the blessing, and it is also said about it, "You, your son, and your daughter." The son heard this and repented, and the father was healed. Because it is the source of the blessing. This is a piyyat, and how can we learn from it? And as for the rest of the verses… "Your son and your daughter." I don't know how to say, are parents punished for the sins of their children even when they are adults?