A noun for “brother” in The Etymologies of the 1930s derived from the root ᴹ√TOR of the same meaning, with a somewhat irregular plural torni (Ety/TOR). Its stem form is torn-, since with most inflected forms the Quenya syncope comes into play and the second o is lost.
Neo-Quenya: In notes from the late 1960s, Tolkien introduced a new word háno for “brother” (VT47/14). However, I think toron might be retained to mean a “metaphorical brother”, a close male associate who may or may not be related by blood, as with such words as melotorni “love-brother, ✱close male friend” or ᴹQ. otorno “sworn brother”. In this sense, háno would be limited to biological relationships, but toron would refer to brotherly (or brother-like) affection.
Son of Elendil in Tolkien’s unfinished “Lost Road” story from the 1930s (LR/49). The name also appeared in The Etymologies where it was glossed “Eadwine” (Old English for “Fortune-friend”) and given as a compound of heren “fortune” and -(n)dil “friend” (Ety/KHER, NIL). In later versions of the Fall of Númenor, this character’s name was switched for that of his father, so that he became Elendil as he was eventually named in The Lord of the Rings.