Dear Rabbi Is it Halacha or is it minhag to visit the kever of a parent on the Yartzeit? What if one is able to contribute to charity on behalf of the parent, light the memorial candle but does not visit on the Yartzeit? Is this wrong not to do? Also, if they have been visiting for several years and then for whatever reasons do not or cannot visit? Thank you so much Rabbi for your kindness and help.
Visiting the kever of a parent is indeed a time honored minhag. The tefilot by the Kever benefit their Neshama. (Pnei Baruch chapter 37). Lighting a candle is also an important minhag which also benefits the neshama and giving Tzedaka is a mitzvah on its own right and is a great act to do in memory of the niftar. Answering your question, if you are unable to visit the kever, the other acts you mentioned are indeed virtuous and beneficial for the Neshama. So you should not feel troubled if for justified reasons you are unable to visit. Many people for reasons of distance or physical incapability can't visit the kever of their parents and find other ways such as torah study and the like to honor their deceased parents. However, if the time is inconvenient visiting the kever at other times even when not the Yahrtzeit is beneficial for the Neshama of the niftar. Besorot tovot