Synonyms for Brother (same or very similar meaning)
WordNet sense 1 (used as a term of address for those male persons engaged in the same movement):
comrade
WordNet sense 2 (a male with the same parents as someone else):
blood brother
WordNet sense 3 (a close friend who accompanies his buddies in their activities):
buddy, chum, crony, pal, sidekick
From the ODE community, based on WordNet
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