SlashFilm affirms the identity of Sherlock’s older smarter brother, Mycroft, in Guy Ritchie’s sequel to the sleuth reboot. Anyone who needs this doppelganger casting choice substantiated need look no further than A. Conan Dolye’s own description of Mycroft:
Heavily built and massive, there was a suggestion of uncouth physical inertia in the figure, but above this unwieldy frame there was perched a head so masterful in its brow, so alert in its steel-gray, deep-set eyes, so firm in its lips, and so subtle in its play of expression, that after the first glance one forgot the gross body and remembered only the dominant mind.