Brotherly, a.
Of or pertaining to brothers; such as is natural for brothers; becoming to brothers; kind; affectionate; as, brotherly love.
Syn. -- Fraternal; kind; affectionate; tender.
1 other Webster entry under this spelling
Brotherly, adv.
Like a brother; affectionately; kindly. "I speak but brotherly of him." Shak.
Shades of meaning
Fernald has no entry of its own for brotherly; he lists it under friendly.
He lists it without comment; the entries above explain its neighbors.