Blessing at the Chuppah During the Year of Mourning

Can a mourner within the year of his mother's passing recite one of the Sheva Brachot at a chuppah?

After thirty days, it is permitted if the chuppah is outside the hall, and he may wear some Shabbat clothing. Before thirty days, participation in the chuppah is prohibited.

The Rema writes in Siman 391, Sif 3: "But he should not enter the house at all when they are celebrating the bride and groom, and so is the custom in Ashkenaz (Tur) and in these countries. And all this is in the house where the wedding is held, and they eat, drink, and rejoice there, but at the chuppah held in the synagogue, where they bless the betrothal and marriage blessings and there is no joy at all, it is permitted immediately after seven days (Hagahot Maimoni). Some prohibit until thirty days (there in the name of Raaviah), and so it seems to me. In some places, they are strict that the mourner stands all twelve months outside the synagogue to hear the blessings (Hagahot Mahari"l). Nevertheless, it seems that a mourner can bless the betrothal and marriage blessings under the chuppah in the synagogue. He can also bring in the groom, as is customary in our country, where two people bring the groom under the chuppah. And he can wear some Shabbat clothing when bringing in, provided it is after 30 days (DA), and so is the custom." And see Shu"t Maharam Mintz 86, which writes that some say it is not a good sign for a mourner to make the blessings, and it is written that everything depends on the custom.