Question: Should a son say Kaddish for his parent who was a rasha (a wicked person)?
Short Answer: Yes. According to most poskim, a son should recite Kaddish for a wicked parent. According to some, this Kaddish may be recited all twelve months. Similarly, a convert may recite Kaddish for a parent.
Question: Should a Sefardi who is saying Kaddish in an Ashkenazi shul recite the Kaddish nusach for Sefardim or the nusach of the Ashkenazi shul? The same question applies in the reverse case – an Ashkenazi davening in a Sefardi shul?
Question: When a parent tells his/her child that he/she does not want Kaddish recited for them, should the child listen?
Short Answer: While the simple understanding is that the child should obey the parent’s request and not recite Kaddish, many Acharonim limit this ruling to specific situations. In most cases, the child should probably recite Kaddish against his parent’s wishes.