The Mitzvah of Comforting Mourners After Shiva

Is there a mitzvah to comfort mourners after the shiva?

If one comforted during the shiva, there is no obligation to return and comfort again. However, if one did not comfort during the shiva, there is a mitzvah to comfort other relatives for thirty days, and for one's father and mother, twelve months, and for a wife who passed away, three festivals.

The Talmud, Moed Katan, page 21b: "One who finds his friend in mourning within twelve months speaks to him words of comfort and does not inquire about his welfare. After twelve months, he inquires about his welfare but does not speak words of comfort, but speaks to him indirectly. Rabbi Meir said: One who finds his friend in mourning after twelve months and speaks words of comfort to him is like a person whose leg was broken and healed. A doctor found him and said: 'Come to me, I will break it and heal it, so that you will know that my medicines are good.' This is not difficult: this refers to one's father and mother, that to other relatives. There too, he speaks words of comfort indirectly? Yes, indeed. And what does it mean that he does not speak words of comfort — in the usual manner, but speaks indirectly.

Meiri wrote about comforting one's father and mother after twelve months, if he wishes. This implies there is no obligation.

However, from Rashi's words in Pesachim, page 49, commentary "Lashavet", it implies there is an obligation, as he wrote: 'He was going to darken the boundary to establish residence there so that he would have from there and beyond two thousand, to go there tomorrow for a permissible matter — he must return immediately, but to establish residence for a mitzvah, such as going tomorrow beyond the boundary to the house of the mourner or to the feast — this is like going to slaughter the Passover offering.' And this is on the eve of Passover, and one who sits shiva, the festival cancels the law of shiva for him, as explained in Shulchan Aruch, section 397, paragraph 1. This proves there is a mitzvah to comfort mourners after shiva. (And although it can be refuted and said that Rashi means he knows there is a relative who does not know about the death of his relative, and will inform him on the festival, nevertheless, this is not the simple understanding of Rashi's words).

And this is also implied from the language of the Shulchan Aruch, section 385, paragraph 2, where it does not say "if he wishes." And here are his words: "One who finds his friend in mourning within 30 days speaks to him words of comfort and does not inquire about his welfare. After 30 days, he inquires about his welfare and does not speak words of comfort in the usual manner, but indirectly, not mentioning the name of the deceased, but says to him: 'May you find comfort.' If his wife died and he married another, he does not enter his house to speak words of comfort. If he finds him in the market, he says to him: 'May you find comfort,' in a soft voice and with seriousness. But if he did not marry another, he speaks words of comfort until three festivals have passed. And for his father and mother, he speaks words of comfort all twelve months; after twelve months, he speaks to him indirectly."

And the Aruch HaShulchan, Yoreh Deah, section 385, paragraph 3, wrote: "And know that now it is not customary also to say 'May you find comfort' after 30 days."