Yes, I believe it is. I don’t know where it is written, but I did learn it in school many centuries ago when I was a youngster. So I don’t know if it is written in the Torah, mishneh, etc. Or it was in a sefer written by a RAV. When a family is in such a situation they should ask their own Rav. There are so many situations later in life, such as infertility where questions come up such as “did you hurt anyone in shiduchim that you need to ask mechilah from”. When it comes to shidduchim, marriage, sholom bayis issues, etc., don’t play fast and furious (or foolish). Ask a dependable Rav and do it right. There is no reason why a younger sibling should not ask permission from an older one. If the older sibling is not loving, caring and generous enough to allow the younger sibling to get on with their life and not wait for them, then a Rav should be consulted.
