Question: If a parent had passed away for less than a year, can one celebrates events, such as the mooncake festival?
Answer: It is generally not a Buddhist concern, this issue of whether it is alright to have festive celebrations within a year of the passing of relatives, but a common Chinese cultural custom. The rationale behind it is that since one is supposed to be ‘mourning’, one should be in ‘grief’ and not in the mood for celebrations, unless one did not really care for the deceased. Seen in this sense, it makes some sense. (It can take up to 49 days for one to take rebirth.)
However, in Buddhism, doing what is practical to help the deceased to have a better rebirth is more important that having yearlong grief, which does nothing for the deceased, other than to possibly spur attachment and grief on both sides. In other words, if you feel that enough efforts have been exerted to help the deceased, and that others should not feel offended by your ‘early’ celebrations, it is alright. Ironically, even if one feels it is alright to celebrate, others around might not. This is when you have to decide if ‘creating’ a misunderstanding is worth it.