brotherly vs brother

brotherly is not a noun while brother is a noun.

Word	Noun	Adjective	Verb	Adverb
brotherly	No	Yes	No	Yes
brother	Yes	No	No	No

brotherly (noun)	brother (noun)
	a male with the same parents as someone else
	a male person who is a fellow member (of a fraternity or religion or other group)
	a close friend who accompanies his buddies in their activities
	used as a term of address for those male persons engaged in the same movement

brotherly (adjective)	brother (adjective)
like or characteristic of or befitting a brother

brotherly (adverb)	brother (adverb)
(archaic as adverb) in a manner characteristic of a brother