The holiday of Ĥanuka is a time of joy, praise, and thanksgiving. Therefore, one may not fast or eulogize on Ĥanuka, even on the yahrtzeit of a parent – when many people customarily fast – that coincides with Ĥanuka. Similarly, a bride and groom who follow the custom of Ashkenazim and some Sephardim to fast on their wedding day do not do so on Ĥanuka.
Likewise, one may not deliver a eulogy on Ĥanuka at a funeral or at a memorial service at the end of the shiva or shloshim period. The only exception is a Torah scholar’s funeral, where one may eulogize in the presence of the body (Shabbat 21b; sa, Rema 670:1). The laws of mourning apply on Ĥanuka as on any other day (sa 696:4).
Many people refrain from visiting cemeteries on Ĥanuka, whether on a yahrtzeit or at the conclusion of shiva or shloshim, because such visits are liable to elicit crying and mourning, which are forbidden on Ĥanuka. Instead, they should visit the cemetery either before or after Ĥanuka. Others, including Moroccan Jews and some Jews from other communities, visit cemeteries even on Ĥanuka. According to all customs, one may visit the graves of righteous people on Ĥanuka (Ben Ish Ĥai, Vayeshev 22; see also Gesher Ha-ĥayim 29:6).
Sephardic custom is to recite Tziduk Ha-din on Ĥanuka (sa 420:2), while Ashkenazic custom is not to do so (Rema 420:2, 683:1). According to all customs, Taĥanun and La-menatze’aĥ are omitted on Ĥanuka. Likewise, mourners customarily do not lead prayers on Ĥanuka.
. mb 683:1 and Kaf Ha-ĥayim 683:5 state that a mourner may not lead Shaĥarit on Ĥanuka or Rosh Ĥodesh, but he may lead Minĥa or Ma’ariv. bhl §132, however, states that mourners do not lead the services on any day when La-menatze’aĥ is omitted. The source for this is Maharil §22. The prevalent custom is that mourners do not lead any service on Ĥanuka or Rosh Ĥodesh.