Can I say kaddish for my grandparents?

Question:

I have recently been reading up on how to honor the dead. I really believe that I can benefit my loved ones in the next worlds by doing good things in their honor in this one. I recently found out the dates of their deaths, and my question is: Can I say kaddish for grandparents, aunts, or my baby brother who passed away? Some of my grandparents passed away nearly thirty years ago, and my brother was only alive for two weeks.

Thank you for your time. I look forward to your answer and in putting your words into action.

Answer:

It is very commendable of you to want to say kaddish for these relatives of yours. No matter how many years have passed since their deaths, the recitation of kaddish on their yahrtzeit is very beneficial for their souls. The main question, however, is whether or not your own parents are alive. If both your parents are alive, then customarily you would not say mourners' kaddish in the merit of anyone else. If only one parent is alive, then there is more flexibility. (Either way, your own rabbi should be consulted if one or both of your parents are alive.)

The second question is whether or not anyone else is saying kaddish for these relatives on their yahrtzeits. If you are incapable of saying kaddish due to the aforementioned factor, you should certainly arrange for someone else to recite the kaddish on their yahrtzeits. If you do not know anyone who can do this task, see Arrange Kaddish for a Loved One.

Finally, I would like to caution you against taking upon yourself more than your can really manage, despite your worthy intentions. For this issue, you would be well advised to consult with your spiritual mentor, someone who knows you personally.

Regarding your brother who passed away at two weeks old: no kaddish or the like is called for by Jewish law, since he was taken before he reached the age of one month old, the age at which a life is proven to be viable.

In any event, you can definitely drop a few extra coins into a charity box on his yahrtzeit, and recite the traditional mishnayot in his memory, and for the continued elevation of his soul. These steps should also be followed on the yahrtzeits of your other departed relative. (see Kaddish and memorial: aiding the soul's ascent: The Basics.)

May the Almighty hasten the fulfillment of the ultimate promise, "You who repose in the dust: Awaken and sing joyful praises!"1

I would also like to point out something which you may already be aware of: a yahrtzeit is observed on the anniversary of the death according to the Jewish calendar. Our Yahrtzit Calculator will instantly convert for you any secular date to its corresponding Jewish one.

Rabbi Eliezer Danzinger for Chabad.org