Participation in a Hanukkah Party During the Year of Mourning

Is it permissible for someone in the year of mourning for their mother to attend a Hanukkah party with music and songs?

According to the Shulchan Aruch, it is forbidden. During Hanukkah, all the laws of mourning are observed. According to the Rema, it is permissible to attend a Hanukkah party within the year if words of Torah are spoken there. If it is at his home, it is even permissible to eat.

Shulchan Aruch, Orach Chaim, Siman 696, Sif 4: "All mourning practices are observed during Hanukkah." And it is written in Shulchan Aruch, Siman 670, Sif 2: "The many meals that are increased during these days are optional meals, as they were not established for feasting and joy." The Rema writes: "And there is an opinion that there is some mitzvah in increasing the meals, because in those days there was the dedication of the altar (Maharal of Prague). And it is customary to sing hymns and praises at the meals that are increased, and then it becomes a mitzvah meal." Therefore, the opinion of our teacher, the Rav, is that if words of Torah are spoken at a Hanukkah party, an Ashkenazi within the year of mourning for one of his parents may participate. And although the Rema wrote in Siman 391, Sif 2, that it is customary not to participate in any meal in the world for all twelve months outside his home, here it is different because the mourner himself is obligated in this meal, and it is not similar to a meal that is a mitzvah for others, which he is forbidden to participate in.