Question: The professional boxer, who held the WBO ligh-middleweight from 2015-2016, has a younger brother who is also a professional boxer; what is this brother's name?
Sentence (from "Callum Smith"): Callum Smith (born 23 April 1990) is a British professional boxer who competes in the super-middleweight division, and held the European, the British, and the WBC Silver titles between 2015 and 2017.
Relevant evidence: Yes