Wolf, my condolences. I don’t know you personally (at least, I think not), but it seems that your mom raised a mensch.
I also didn’t say anything when others davened during my aveilut. I think there were 2 or 3 others in aveilut at the same time I was, and we just naturally took turns. A yahrzeit always took precedence (plus, I was glad to have the day off).
Regarding the OP, the yahrzeit days are a bit stressful, especially since I can’t visit the graves. However, I daven for the amud, bring some schnapps and nosh in the morning, and spend the day thinking about (and missing) the parent. I also sponsor the shiur I attend on the Shabbat before.