Question:
What is the halacha if we want to get together on chanukah for a supper siblings and children in the year for our father
Answer:
R’ S. Z. Auerbach is quoted in Halichos Shlomo vol. 2 18-13, that it is permitted an avel to attend a family Chanukah party, however they should be careful only to sing chanukah related songs.
Best Wishes