Halocho #216 - Yahrzeit on non-existing days

Yesterday we learned that the months of Marcheshvan and Kislev sometimes both have 30 days, sometimes both have 29 days and sometimes follow the regular order with Marcheshvan having 29 days and Kislev 30. The 30th day of the month as well as the first day of the month are Rosh Chodesh. If the month ending has only 29 days then there's only one day of Rosh Chodesh. If a person died on 30 Marcheshvan, do we say he died on the last day of Marcheshvan or on Rosh Chodesh Kislev? - If the year of the first anniversary also has a 30 Marcheshvan then the Yahrzeit will henceforth always be on the first day of Rosh Chodesh Kislev; be it 30 Marcheshvan or 1 Kislev. - If the year of the first anniversary does not have a 30 Marcheshvan then the Yahrzeit will henceforth always be on the last day of Marcheshvan; be it 30 Marcheshvan (1st day Rosh Chodesh) or 29 Marcheshvan (Erev Rosh Chodesh). In this last case, if possible Kaddish should also be said on Rosh Chodesh. Source: Kitzur Shulchan Aruch 221:4 - Danny Monday, 4 Kislev 5769

Please daven for a complete recovery for Tamar bat Naama - תמר בת נעמה