Q. Can someone who still has living parents light a yortzait candle for a deceased friend? Is permission from the parents required?

A. One who has a father and mother should not recite kaddish yatom ((Pischei Teshuva Y.D. 376: 4) and according to some Poskim even with their approval.
However, on lighting a yortzait candle for a deceased friend or relative, Horav Shlomo Miller’s Shlit’a opinion is that it is permitted, but he should first consult with his parents.
The Rov mainains that lighting candles for Rashb’i on Lag Baomer or for other Tzadikim in their yortzait is permitted

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a