My brother and I share the same Ashkenazi parents but there are a few differences in observance because of where we live. I celebrate one seder, he two; Pesach is 7 days with eight for him; and for me 2 days chag, for him 4. Nor do I avoid kitniot
If you are born in the month of Adar, anniversaries, barmitzvahs and wedding anniversaries, all fall in Adar 2 in a leap year. My rabbi assures me that the fast of Esther and Purim is not this week, but next month. Nor do we celebrate these occasions twice, once this month, once next.
But, if like our mother, you die in Adar, two days before Purim, both his shul in London and mine in Netanya, seem to believe that we have yahrzeit this week and that, somehow, we have two yahrzeits for one death. My other orthodox shul, in Bournemouth, has advised me that my yahrzeit falls on March 17, and I agree.
The United Synagogue in the UK advised my brother that their explanation for Adar 1 comes from the Shulchan Aruch but I looked it up and it clearly states Adar 2. The US response is that the SA was written by a Sephardi and that a rabbi from Cracow some 500 years ago decided that things were different for Ashkenazis (but not for Pesach in Israel, apparently).
And so to the questions. What is the logic in having different rules for life and death? And what is the logic that holds that our mother’s yahrzeit can fall four weeks and three days before the actuality?
As for Ashkenazi and Sephardi, surely a Jew is a Jew is a Jew?
PS. If you are celebrating Purim in Adar 1, chag sameach!
Shulchan Aruch rules that the yahrzeit, like other halachos you mention, is observed in the second Adar. This would be the custom for Sephardic Jews.
Rema, however, whose rulings are followed by Ashkenazi Jewry, rules that although concerning bar mitzvah, a child born on a regular adar becomes bar mitzvah (in a leap year) in adar beis (55:10), the yartzeit is commemorated in adar aleph (568:7). There are various approahces for resolving this matter, as we have discussed here.
Note, however, that Rema himself writes that one should observe the yahrzeit on both Adar months, and this is the preferable practice.
Concerning Purim, the Talmud writes that Purim is observed on the second Adar, so that this question, unlike the others you mention, is not raised by halachic authorities.
A Jew is indeed a Jew, but different Jews follow different customs, though this is sometimes confusing!
Chag Sameach to you, too, when the time comes!