143:8 A person is obligated to honor his parents even after their death. If one mentions them within 12 months of their passing, whether verbally or in writing, he says or writes, “Behold I am their atonement from the grave,” the intention of which is, “Let all the evil that is deserving to come upon his soul be on me.” After 12 months, a soul has received whatever punishment it earned, since the souls of evil Jews are only judged in Gehinnom for 12 months. Therefore, one would say or write, “Remember him (or her) for blessing for life in the World to Come.”
143:9 Even if one’s parent was evil and a sinner, one must honor and defer to him. Even the product of an incestuous or adulterous union is obligated to honor and defer to his parents. Some authorities say that a person is not obligated to honor a wicked parent as long as he hasn’t repented. Nevertheless, it is prohibited to cause him distress. One should be stringent in this matter and follow the first opinion.