The Collaborative International Dictionary of English v.0.48:

Brotherly \Broth"er*ly\, a.
   Of or pertaining to brothers; such as is natural for
   brothers; becoming to brothers; kind; affectionate; as,
   brotherly love.
   [1913 Webster]

   Syn: Fraternal; kind; affectionate; tender.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Brotherly \Broth"er*ly\, adv.
   Like a brother; affectionately; kindly. "I speak but
   brotherly of him." --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

brotherly
    adv 1: (archaic as adverb) in a brotherly manner
    adj 1: like or characteristic of or befitting a brother;
           "brotherly feelings"; "close fraternal ties" [syn:
           brotherly, brotherlike, fraternal] [ant:
           sisterlike, sisterly, sororal]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "brotherly":
   Christian, Christlike, Christly, affectionate, agreeable, amiable,
   amicable, benign, benignant, compassionate, congenial, cordial,
   decent, devoted, favorable, fraternal, friendlike, friendly, good,
   gracious, harmonious, human, humane, kind, kindhearted, kindly,
   kindly-disposed, loving, loyal, neighborlike, neighborly, nice,
   peaceable, pleasant, simpatico, sisterly, sociable, softhearted,
   sympathetic, sympathique, sympathizing, tender, tenderhearted,
   unhostile, warm, warmhearted, well-affected, well-disposed,
   well-intentioned, well-meaning, well-meant