I do think that's a cockerel.
In any breed, this age is still too young to count on a male having sex feathers. 13 weeks is more common. Add in the fact Brahmas are giants and slower to mature, and your boy may not get sex feathers for a few months.
Hi everyone just an update posted this months ago she turned out to be a girl thank god of the only 4 I'm allowed to have they r all girls!)20 weeks now