Attending a funeral is a mitzva--that of honoring the dead person--but in attending a parent's funeral, there is the added mitzva of honoring a parent.

Adult (at least bar mitzva or bat mitzva) offspring should attend their parent's funeral, unless there is a financial, health, or other significant reason not to attend. There is no requirement for minor offspring to attend a funeral for a parent. RMH recommends consulting a rabbi before having a minor go to any funeral, including for the child's parent.

NoteIf both parents are still alive, it is not customary to go to the cemetery for any funeral except for a close relative, but it is a mitzva to attend the eulogies and ceremony beforehand.