I am ashamed to admit that I completely forgot to observe my Mother’s Yahrzeit. This is not because I do not remember her - I think about her every day even though she has been gone for 40 years. What should I do?

Sometimes, even when one remembers the Yahrzeit there are some days of the year when some of the customs cannot be observed. For example during the month of Nissan the custom is that "Kel malei Rachamim" is not to be recited. Or there is the custom that one says the "kel malei etc. on the day the torah is read and not always does this fall on the day of the Yahrtzeit. In the two above cases the custom is to say the prayer on a day preceding the Yahrtzeit. We therefore see that there are precedents in which some of the customs are not kept on time. I was told by the former Chief Rabbi of Israel, Rav Avraham Shapira zt'l that the neshama of the deceased is still benefitted by the various customs even though they don't take place on the day of the Yahrtzeit. So although there were would have been an additional virtue had things been done in the proper time and this is the way things should be done to begin with, whatever you arrange to be done on your mother's Yahrzeit can be done later as well. The primary merit for the soul of the deceased is the giving of Tzedaka which can definitely done any time of the year. Perhaps to compensate for the belated observance you may want to give this year an additional amount of Tzedaka for the merit of your mother's neshama. May the memory of your mother be for a blessing. Besorot Tovot and Shana Tova.