Question:
Today was my son’s 11th yahrtzeit. I was unable to go to the kever due to another child being in the hospital and being discharged only today. (My family did go.) Is there any point in going on Sunday or is that just like going at any other time?
Answer:
It is said that if one can not go to the kever on the yahrtziet, that they can still go within three days of the yahrtziet, which would include Sunday
Sources:
The Laws of Aveilus pg. 322.
