wise elder brother; polite term for another's older brother or senior
A formal, respectful pronoun used to refer to someone else's older brother or a respected senior. Not used for one's own brother. Rare in modern casual speech; mainly found in formal letters or historical contexts.
I am always indebted to your wise elder brother.
先日は賢兄よりご丁寧なお手紙を頂戴し、恐縮しております。
The other day I received a very kind letter from your esteemed brother, for which I am most grateful.