Do Not Remind Him of His Past
A person who now lives rightly must not be reminded of his earlier mistakes or the shortcomings of his family.
A teaching ofRav Yisroel Meir HaKohen Kagan of Radinהרב ישראל מאיר בן אריה לייב קגןProfile ›
The Chofetz Chaim teaches that lashon hara is not limited to current faults. It includes reminding a person of the deeds of his parents and relatives, or of mistakes he made earlier in life, whether between him and Hashem or between him and other people. If he now behaves correctly, it is forbidden to shame him with the past, even though everything said is true. Even something he is seen doing wrong today, in a matter between man and Hashem, may not be spoken of behind his back, unless the conditions set out later in the sefer are met. In this way the Chofetz Chaim protects the chance to change. A person who knows that his past will not be held against him is much freer to become someone better.
Source: Chafetz Chaim, Part One, The Prohibition Against Lashon Hara, Principle 4:1
Think of someone, perhaps in your family or your community, whom you still associate with an old mistake. Today, decide not to bring it up, not to him and not to anyone else, and treat him as the person he is now. If the old story comes into the conversation, change the subject kindly. Then do one small thing that shows him you see the better version, such as a warm greeting or an honest compliment. You may help him become that person.