The Ben Ish Chai says that the day of a yartzheit is not limited. Even if a son lives 100 years after the father or mother died, he must make a yartzheit throughout his entire life as usual, with saying kadish, lighting a candle, giving tzedakah and learning according to his ability. This is because even if he passed away from this world and was saved from punishment and enters Gan Eden, the soul of the deceased doesn’t acquire complete ascension at one time. Rather it ascends levels at different times. There is a soul that even until 1,000 years will not reach all the levels that it’s fitting for. It ascends throughout the years, ascension after ascension until it reaches the zenith that it’s fitting to. According to the Chassam Sofer there is no endpoint. Rather the soul can keep ascending, as he writes ושוב ביארצייט מעיינים בדינו ומתעלה וכן לעולם.
On a yartzheit one should also say praises of the deceased in order to elevate them to a higher level in Gan Eden (Taamai Haminhagim, p. 447).
Shu”t Chassam Sofer Volume 1, Orach Chaim, 14. Artscroll began by R' Meir Zlotowitz deciding to translate Megillas Esther into English in 1976. He did this in memory of a friend of his who didn't have children. From the enthusiastic public response of the Megillas Esther translation, Artscroll expanded until it eventually morphed into what it is today. Imagine the aliyas neshama of R' Meir Zlotowitz’s friend for whom it was originally started.
